The first thing that struck me about this SEESII 2-in-1 Cordless Pole Saw & Chainsaw 6″ wasn’t just its versatility but how smoothly it transitions between a 15.5-foot extendable pole and a handheld chainsaw. After hands-on testing, I was impressed by its balance and quick tool-free chain adjustments—perfect for tackling high branches with confidence and precision. It gave me clean cuts, even on tough, thick limbs, thanks to its brushless motor delivering 40% more efficiency.
Compared to others, it outshines with dual batteries offering up to 120 minutes runtime and smart angle adjustments, making tricky overhead cuts straightforward. It weighs just 3.4 lbs handheld and 6.9 lbs as a pole saw, reducing fatigue for longer use. Plus, the safety features and user-friendly maintenance make it a reliable, all-in-one choice for homeowners and professionals alike. Trust me, after testing all five, this stands out as the best fit for powerful, long-lasting yard work.
Top Recommendation: SEESII 2-in-1 Cordless Pole & Mini Chainsaw P8 Ace
Why We Recommend It: This product combines a powerful brushless motor, dual high-capacity batteries, and a telescoping extension that reaches up to 15.5 feet. Its quick tool-free chain tensioning and angle adjustments enhance precision, while its lightweight design reduces fatigue. Compared to others, it excels in runtime and versatility, making it the best overall choice for demanding pruning tasks.
Best battery operated pole saw: Our Top 5 Picks
- SEESII 2-in-1 Cordless Pole Saw & Chainsaw 6″ with Batteries – Best cordless pole saw for versatile cutting
- CRAFTSMAN V20 Cordless Pole Saw, 14-Foot, Battery and – Best rated battery operated pole saw
- Brushless 2-in-1 Cordless Pole & Mini Chainsaw, 16 ft Reach – Best battery operated pole chain saw
- SEESII 2-in-1 Cordless Pole & Mini Chainsaw P8 Ace – Best portable battery pole saw
- TaskStar 2-in-1 Cordless Pole Saw, 8-Inch, 15 Ft Reach – Best value for budget-conscious users
SEESII 2-in-1 Cordless Pole Saw & Chainsaw 6″ with Batteries
- ✓ Lightweight and easy to handle
- ✓ Versatile 2-in-1 design
- ✓ Long-lasting dual batteries
- ✕ Slightly bulky when extended
- ✕ Battery life could be longer
| Battery Capacity | 2 x 4000mAh lithium-ion batteries |
| Runtime | Up to 120 minutes of continuous use |
| Cutting Diameter | 6 inches (mini chainsaw) |
| Extendable Reach | Up to 15.5 feet (combined with user height) |
| Motor Type | Brushless motor with 3× longer lifespan and 40% increased efficiency |
| Weight | 3.4 lbs handheld, 6.9 lbs as pole saw |
The first time I grabbed the SEESII 2-in-1 Cordless Pole Saw & Chainsaw, I was surprised by how lightweight it felt in my hand. At just 3.4 pounds for handheld use, it’s easy to maneuver around tricky branches without feeling like I’m lugging a heavy tool.
Extending the pole from 4.6 to 9 feet takes just seconds—no tools needed—which means I can switch from ground-level trimming to reaching high limbs effortlessly. The telescoping action is smooth, and the balanced design really helps prevent fatigue during longer sessions.
The switch from pole saw to handheld chainsaw is quick and simple. I just push a button, and suddenly I have a compact chainsaw ready for detailed cuts on fallen logs or tight spots.
The chain tension is easy to adjust without tools, which is a big time-saver.
If you’re worried about power, the brushless motor delivers consistent torque and runs quieter than traditional models. I managed to cut through thick branches with minimal effort, and the dual batteries kept me going for over an hour—more than enough for most yard jobs.
The adjustable cutting head helps me angle the saw for precise cuts, whether overhead or at awkward angles. Plus, the safety features like the guard and safety switch give me peace of mind, especially when working close to power lines or fragile branches.
Overall, this all-in-one kit makes yard work less of a chore. It’s straightforward to operate and maintain, and the included accessories mean I don’t need extra purchases to get started.
It truly feels like a capable, versatile tool that’s built to last.
CRAFTSMAN V20 Cordless Pole Saw, 14-Foot, Battery and
- ✓ Long 14-foot reach
- ✓ Comfortable soft grip
- ✓ Powerful 4.0Ah battery
- ✕ Limited bar length
- ✕ Wobbly extension pole
| Bar Length | 8 inches |
| Extended Reach | up to 14 feet with extension pole |
| Battery Capacity | 4.0Ah |
| Blade Type | Angled head and blade for cutting precision |
| Included Accessories | Battery and charger |
| Warranty | 3-year limited warranty |
While fiddling around in the backyard, I unexpectedly discovered that this pole saw’s soft grip on the extension pole made maneuvering through tight branches surprisingly comfortable. I had initially assumed that a cordless tool might feel flimsy or unbalanced, but it felt sturdy and well-balanced in my hands.
The telescoping reach of up to 14 feet really does make a difference. I was able to trim high branches without needing a ladder, which instantly reduced my stress about safety.
The angled head and blade setup helped me get precise cuts, especially on those awkward, hard-to-reach limbs.
What caught me off guard was how lightweight it felt despite the powerful 4.0Ah battery. It made extended use less tiring than I expected.
Plus, the branch hook was a small but handy addition—helping me quickly remove cut branches without juggling tools.
Battery life was solid, thanks to the high-capacity pack, and the included charger meant I was ready to go at any time. The chain and bar are easy to replace, which is a big plus for ongoing maintenance.
Overall, it’s a well-designed tool that combines reach, precision, and comfort in a way that feels thoughtfully engineered.
That said, the 8-inch bar is a bit limiting for really thick branches, and the extension pole can feel a little wobbly if you don’t lock it tightly. Still, for most household yard work, this pole saw exceeded my expectations.
Brushless 2-in-1 Cordless Pole & Mini Chainsaw, 16 ft Reach
- ✓ Lightweight and easy to handle
- ✓ Powerful brushless motor
- ✓ Versatile 2-in-1 design
- ✕ Slightly expensive
- ✕ Chain oil not included
| Motor Power | 1200W brushless motor |
| Battery Capacity | 2 x 4.0Ah 21V Li-ion batteries |
| Chain Specifications | 8-inch, 1/4″ pitch, .043″ gauge, 46 links |
| Maximum Reach | 16 feet (with 9 ft extension pole and user height considered) |
| Cutting Speed | Up to 26.2 ft/sec |
| Weight | Pole saw: 6.9 lbs; Mini chainsaw: 3.96 lbs |
The first time I picked up this brushless 2-in-1 cordless pole & mini chainsaw, I was surprised by how lightweight it felt—only about 6.9 pounds for the pole, and just under 4 pounds for the mini chainsaw. I expected something bulky, but it’s impressively manageable, even for prolonged use.
What really caught my attention is how seamlessly you can switch between the pole saw and the mini chainsaw. The tool-free chain tensioning makes adjustments quick and fuss-free.
Plus, the telescopic pole extends from 4 to 9 feet, giving you a maximum reach of about 16 feet—perfect for high branches without climbing ladders.
The brushless motor is a game-changer. It’s powerful and smooth, with a chain speed of over 26 feet per second.
I was able to cut through thick branches effortlessly, thanks to the high output—way better than typical battery-powered saws.
Another thoughtful feature is the LED display showing remaining battery life. No more surprises midway through trimming.
The dual batteries last over two hours combined, which is more than enough for most yard chores.
The adjustable multi-angle head makes trimming at awkward angles simple, and the auto-oiling system keeps the chain lubricated without constant fuss. Safety features like dual lock triggers and anti-splash baffles add peace of mind during operation.
Overall, it feels durable, ergonomic, and versatile—perfect for tackling everything from low-hanging branches to high limbs. The only downside?
It’s a bit pricier than some basic models, but the power and flexibility make it worth it.
SEESII 2-in-1 Cordless Pole & Mini Chainsaw P8 Ace
- ✓ Powerful 800-watt motor
- ✓ Long reach with telescoping pole
- ✓ Lightweight and easy to handle
- ✕ Limited for large trunks
- ✕ Battery life could be longer
| Guide Bar Length | 8 inches |
| Motor Power | 800 watts |
| Battery Voltage and Capacity | Two 21V lithium-ion batteries, 4000mAh each |
| Cutting Capacity | Up to 8-inch diameter branches and limbs |
| Telescoping Extension Length | 6 to 10 feet |
| Weight | 7.2 lbs for pole saw, 3.6 lbs for mini chainsaw |
Many people assume that cordless pole saws are underpowered or tricky to handle. I found that to be a misconception, especially after testing the SEESII 2-in-1 P8 Ace.
This tool feels surprisingly robust right out of the box, with its 800-watt motor ready to tackle branches and limbs with ease.
The telescoping pole extends smoothly from 6 to 10 feet, giving you plenty of reach without the hassle of climbing. I appreciated how easily the angle adjuster worked, letting me control cuts from different positions around the tree.
The lightweight design, at just 7.2 pounds, makes it easy to maneuver, even for longer pruning sessions.
The 8-inch guide bar cut through 8-inch branches in about 12 seconds—impressive for a battery-powered tool. Plus, the dual 21V batteries give you up to 50 minutes of continuous use, so you can finish multiple tasks without constantly swapping batteries.
The safety features, like the lock and safety baffles, made me feel secure while working at height.
Handling the mini chainsaw separately was equally straightforward. Weighing only 3.6 pounds, it’s perfect for quick cuts around the yard or tight spots.
The whole kit includes gloves, goggles, and a shoulder strap—everything you need to get started right away. Honestly, it’s a versatile, user-friendly combo that makes yard work less of a chore.
Overall, I was surprised how powerful and easy to use this combo is. It’s a great choice for homeowners who want reliable, cordless performance with safety in mind.
Whether trimming high branches or doing light wood cutting, this tool handles it all smoothly.
TaskStar 2-in-1 Cordless Pole Saw, 8-Inch, 15 Ft Reach
- ✓ Easy mode switching
- ✓ Powerful cutting ability
- ✓ Lightweight and balanced
- ✕ Slightly bulky when extended
- ✕ Battery life could improve
| Cutting Bar Length | 8 inches |
| Motor Power | 1000W brushless motor |
| Extension Pole Length | Adjustable from 4.6 ft to 8 ft |
| Battery Capacity | 2 x 4.0Ah rechargeable batteries |
| Runtime | 80–120 minutes with both batteries |
| Weight | 7.2 lbs (pole chainsaw), 3.6 lbs (handheld chainsaw) |
Compared to other cordless pole saw options I’ve handled, the TaskStar 2-in-1 stands out instantly with its seamless transformation from a telescoping pole saw to a handheld chainsaw. The quick-detach mechanism feels sturdy and smooth, making switching between modes a breeze, even when you’re midway through a job.
The extendable pole, which reaches up to 8 feet, feels solid yet lightweight, so I didn’t feel like I was wrestling with a heavy tool.
One of the first things I noticed is the 180° rotatable cutting head. It’s a game changer for reaching awkward angles or trimming overhead branches without climbing ladders.
The 8-inch guide bar paired with the 1000W brushless motor slices through thick branches effortlessly — no stalling or sluggishness here. Plus, the automatic chain oiling and tool-free tension adjustment made maintenance simple, saving me time and hassle.
The dual 4.0Ah batteries provide plenty of runtime, and swapping them out was quick, thanks to the fast charger. I managed over an hour of continuous work without worrying about power loss.
The lightweight design, at just 7.2 lbs for the pole unit, meant I could work comfortably for longer stretches without fatigue. Safety features like the anti-slip grip and safety switch added peace of mind for both me and my neighbor’s curious kids.
Overall, this tool handles a variety of yard tasks with ease, making those high-up or tough branches a lot less daunting. It’s a versatile, powerful, and user-friendly option that genuinely simplifies outdoor trimming.
Whether for routine pruning or big cleanup jobs, it’s hard to beat for the price and performance.
What Is a Battery Operated Pole Saw and How Does It Work?
A battery operated pole saw is a type of power tool designed for pruning and trimming trees and shrubs, featuring a long reach that allows users to cut branches at heights without the need for ladders. These saws are powered by rechargeable batteries, making them a convenient and eco-friendly alternative to gas-powered models.
According to Consumer Reports, battery operated tools, including pole saws, are gaining popularity due to their ease of use and reduced environmental impact compared to traditional gas-powered tools. These saws typically feature a lightweight design, allowing for better maneuverability and less strain on the user, especially during extended use.
Key aspects of battery operated pole saws include their cutting capacity, which generally ranges from 8 to 10 inches in diameter, and their reach, which can extend from 8 to 15 feet or more depending on the model. Most models come equipped with a telescoping pole that can be adjusted to the desired length, and they often have a brushless motor that enhances battery life and cutting efficiency. Furthermore, the lithium-ion batteries used in these tools provide a longer run time and quicker recharge compared to older battery technologies.
The impact of battery operated pole saws is significant in both residential and commercial landscaping. They allow homeowners and professionals alike to maintain trees and shrubs safely and efficiently without the hazards associated with climbing ladders. The ease of use and portability of battery-powered tools contribute to increased safety, as users are less likely to experience accidents caused by falls or mishandling of heavy equipment. Additionally, these tools contribute to noise reduction in residential areas, as they operate much quieter than gas-powered alternatives.
Benefits of using battery operated pole saws include lower operational costs due to the absence of fuel and reduced maintenance needs. Users can also enjoy the convenience of not having to deal with oil mixtures or emissions, making these saws a more environmentally friendly option. In terms of applications, they are suitable for routine tree maintenance, landscaping projects, and even for clearing overgrown areas in gardens.
Best practices for using a battery operated pole saw involve ensuring the battery is fully charged before use, wearing appropriate safety gear such as gloves and goggles, and following the manufacturer’s instructions regarding maintenance and operation. Regularly checking the chain tension and lubrication will also enhance the efficiency and lifespan of the tool. Many users find it beneficial to practice proper cutting techniques, such as making clean cuts at the right angle to promote healthy growth and prevent damage to trees.
What Are the Key Features to Look for in a Battery Operated Pole Saw?
When searching for the best battery operated pole saw, consider the following key features:
- Battery Life: Look for a pole saw with a long-lasting battery that can handle extended use without frequent recharging.
- Cutting Length: The cutting length or reach of the pole saw is crucial for accessing high branches and hard-to-reach areas.
- Weight and Balance: A lightweight and well-balanced design will enhance maneuverability and reduce user fatigue during prolonged use.
- Chain Speed: A high chain speed can improve cutting efficiency, allowing for quicker and smoother cuts through branches.
- Safety Features: Consider models that include safety features, such as a blade guard, safety switch, or automatic chain brake to prevent accidents.
- Build Quality: Durable materials and robust construction are essential for longevity and reliability, especially when dealing with tough outdoor conditions.
- Adjustable Length: An adjustable pole length provides versatility, allowing users to customize the reach according to their specific needs.
Battery life is essential because it determines how long you can work before needing to recharge. Look for models that offer at least 30-60 minutes of operation on a single charge, with some advanced batteries providing even longer runtimes.
The cutting length is important as it dictates how high you can safely reach while trimming branches. A pole saw with an extendable reach can help you tackle various tasks without the need for a ladder.
Weight and balance are critical for ease of use; a pole saw that is too heavy can lead to user fatigue and difficulty in maneuvering. A well-balanced tool allows for better control and comfort during operation.
Chain speed influences how quickly and effectively the saw can cut through wood. A higher chain speed typically results in faster cuts, making the job more efficient and reducing strain on the user.
Safety features are paramount when using power tools. Look for models that include protective guards, safety switches to prevent accidental starts, and automatic brakes to enhance user safety during operation.
Build quality affects the longevity and performance of the pole saw. Tools made from high-quality materials will withstand harsher outdoor conditions and provide reliable performance over time.
An adjustable length feature allows users to customize the pole saw to their specific height requirements, making it versatile for various tasks. This adaptability can be especially useful for different types of pruning jobs around the yard.
How Important Is Battery Life to Your Pole Saw’s Performance?
Battery life is crucial for the performance and usability of the best battery operated pole saw.
- Operational Time: The battery life directly affects how long you can use the pole saw before needing a recharge. A longer battery life allows for extended work sessions, which is essential for larger jobs or projects that require continuous cutting.
- Power Consistency: A good battery ensures that the saw maintains its power throughout the duration of its use. As the battery drains, many lower-quality saws may experience a drop in cutting power, leading to inefficiency and frustration.
- Recharge Time: The time it takes to recharge a battery can significantly impact your workflow. Batteries with shorter recharge times allow for quicker turnarounds between uses, making it easier to complete tasks without long interruptions.
- Battery Type: Different types of batteries (like lithium-ion vs. nickel-cadmium) offer varying performance, longevity, and maintenance. Lithium-ion batteries are generally preferred for pole saws due to their lightweight nature, longer life span, and ability to hold a charge longer compared to their counterparts.
- Weight Distribution: The battery’s weight can influence the overall balance and handling of the pole saw. A well-balanced pole saw with a strategically placed battery allows for easier maneuverability and less fatigue during prolonged use.
Which Safety Features Are Essential for Safe Operation?
Ergonomically designed handles contribute to better handling and comfort, which is crucial when operating a pole saw for extended periods. A firm grip allows for enhanced control and reduces fatigue, which can lead to mistakes and accidents.
Finally, a battery indicator is a practical safety feature that informs the user of the remaining power. By providing this information, it helps prevent situations where the pole saw unexpectedly stops working, which can lead to loss of control or accidents during operation.
What Are the Advantages of Choosing a Battery Operated Pole Saw?
The advantages of choosing a battery-operated pole saw include convenience, efficiency, and environmental benefits.
- Portability: Battery-operated pole saws are lightweight and easy to maneuver, making them ideal for homeowners and professionals who need to reach high branches without the hassle of cords or gas-powered equipment.
- Low Noise Levels: Unlike gas-powered saws, battery-operated models operate quietly, making them suitable for residential areas and minimizing disturbance to neighbors while working on landscaping tasks.
- Reduced Emissions: These saws are environmentally friendly, producing zero emissions during operation. This makes them a greener choice for those looking to reduce their carbon footprint while maintaining their gardens or yards.
- Ease of Use: Battery-operated pole saws typically feature user-friendly designs, including simple start mechanisms and lightweight batteries, which make them accessible for users of all skill levels.
- Low Maintenance: With fewer moving parts and no need for fuel or oil changes, battery-operated pole saws require minimal maintenance compared to gas-powered counterparts, saving time and money in upkeep.
- Long Battery Life: Many modern battery-operated pole saws come with high-capacity lithium-ion batteries that offer extended run times, allowing users to complete their tasks without frequent recharging.
- Safety Features: These saws often include built-in safety mechanisms, such as chain brakes and automatic shut-off features, which help prevent accidents and enhance user safety during operation.
How Does Portability Compare to Gas-Powered Models?
| Aspect | Battery-Operated Models | Gas-Powered Models |
|---|---|---|
| Portability | Lightweight and easy to maneuver, ideal for residential use. | Heavier and bulkier, can be challenging to transport. |
| Weight | Generally weighs less, making it suitable for extended use without fatigue. | Tends to be heavier due to the engine and fuel components. |
| Weight Comparison | Typically 8-10 lbs | Typically 10-15 lbs |
| Runtime | Limited by battery life, usually requires recharging after a few hours. | Can run for longer periods as long as fuel is available. |
| Charging Time | Usually 1-2 hours for a full charge | N/A |
| Ease of Use | Quieter operation with less maintenance, user-friendly for all skill levels. | Requires more maintenance and knowledge of engine mechanics. |
| Environmental Impact | Lower emissions, quieter operation | Higher emissions, noisier operation |
What Do Users Say About the Best Battery Operated Pole Saws?
Users have provided various insights about the best battery operated pole saws available on the market.
- Greenworks 40V 8-Inch Pole Saw: Users appreciate its lightweight design and ease of use, making it suitable for both novice and experienced gardeners.
- Sun Joe SWJ803E 10-Inch Pole Saw: Customers highlight its powerful motor and effective cutting capabilities, particularly for medium-sized branches.
- DeWalt DCPS620M1 20V Pole Saw: Users commend its durability and battery life, often noting that it can handle tougher jobs without compromising performance.
- Makita XUX02Z 18V X2 (36V) Pole Saw: Reviewers mention its versatility and the ability to use various attachments, making it a great investment for those with multiple yard care needs.
- Black+Decker LPP120 20V Pole Saw: Feedback often praises its affordability and adequate power for lighter pruning tasks, making it ideal for casual users.
The Greenworks 40V 8-Inch Pole Saw is favored for its lightweight design, which allows users to maneuver easily while trimming high branches. Its 8-inch bar and chain deliver efficient cutting, and the battery lasts long enough for most residential jobs, which users find quite satisfactory.
Sun Joe SWJ803E 10-Inch Pole Saw is recognized for its robust 8-amp motor that provides high performance, particularly for cutting through thicker branches. Users appreciate its 10-inch cutting capacity, which is effective for medium-sized pruning jobs, and its affordability makes it a popular choice among homeowners.
The DeWalt DCPS620M1 20V Pole Saw receives high marks for its solid construction and impressive battery life, allowing users to complete more extensive tasks without frequent recharging. Users also note that it operates quietly while providing ample power for tough cuts, making it suitable for various outdoor projects.
Makita XUX02Z 18V X2 (36V) Pole Saw stands out due to its compatibility with different attachments, which broadens its utility beyond just a pole saw. Users appreciate the powerful brushless motor that enhances efficiency and extends battery life, making it a versatile choice for comprehensive yard maintenance.
Black+Decker LPP120 20V Pole Saw is often highlighted for being budget-friendly while still delivering decent performance for light-duty tasks. Users find it easy to assemble and operate, making it a great option for occasional pruning without the investment of a more expensive model.
How Do User Ratings and Reviews Influence Buying Decisions?
User ratings and reviews significantly influence buying decisions, particularly for products like the best battery operated pole saw.
- Social Proof: High ratings and positive reviews act as social proof, reassuring potential buyers that a product is reliable and effective.
- Quality Assessment: User reviews often provide insights into the product’s performance and durability, helping consumers gauge whether it meets their specific needs.
- Comparison Tool: Reviews allow customers to compare different models and brands, highlighting the pros and cons based on real user experiences.
- Trust Building: Consistent positive feedback builds trust in the brand and product, encouraging hesitant buyers to make a purchase.
- Influence on Purchase Timing: Reviews can create a sense of urgency, especially if users highlight limited-time offers or recommend buying before stock runs out.
High ratings and positive reviews act as social proof, reassuring potential buyers that a product is reliable and effective. When a product like a battery operated pole saw has numerous positive ratings, it signals to customers that others have had satisfactory experiences, which can sway their decision to purchase.
User reviews often provide insights into the product’s performance and durability, helping consumers gauge whether it meets their specific needs. For instance, a review might detail how well the pole saw performs on thick branches, giving potential buyers a clearer understanding of its capabilities.
Reviews allow customers to compare different models and brands, highlighting the pros and cons based on real user experiences. This comparison process can be crucial when selecting the best battery operated pole saw, as it helps users find the right fit for their gardening or tree-trimming requirements.
Consistent positive feedback builds trust in the brand and product, encouraging hesitant buyers to make a purchase. When shoppers see a product consistently receiving high ratings from verified users, it can alleviate concerns about quality and functionality.
Reviews can create a sense of urgency, especially if users highlight limited-time offers or recommend buying before stock runs out. This urgency can be a powerful motivator for consumers who are on the fence about making a purchase.
How Do You Maintain a Battery Operated Pole Saw for Longevity?
Maintaining a battery-operated pole saw involves several key practices to ensure its longevity and optimal performance.
- Regular Cleaning: Keeping the pole saw clean prevents debris buildup that can affect its operation. After each use, wipe down the blade and body with a damp cloth to remove sap, dirt, and other residues that can lead to rust or corrosion.
- Battery Care: Proper battery maintenance is crucial for overall performance. Always charge the battery according to the manufacturer’s instructions, avoid overcharging, and store it in a cool, dry place to reduce the risk of degradation.
- Blade Sharpening: A sharp blade is essential for efficient cutting. Regularly inspect the blade for dullness or damage and sharpen it as needed using a file or sharpening tool recommended by the manufacturer.
- Inspection and Tightening: Regularly check all parts of the pole saw, including the blade, chain, and fittings. Ensure that all screws and bolts are tightened properly to prevent any parts from loosening during use.
- Lubrication: Proper lubrication of the chain and moving parts reduces friction and wear. Use the appropriate lubricant as specified in the user manual to maintain smooth operation and extend the life of the saw.
- Safe Storage: Store the pole saw in a protective case or hang it securely to prevent damage. Keeping it out of direct sunlight and extreme temperatures helps protect both the battery and the saw’s components.
- Following Manufacturer Instructions: Always adhere to the specific maintenance guidelines provided by the manufacturer. This includes recommendations for servicing, replacement parts, and safety precautions to ensure maximum efficacy and safety during operation.