Full Review ⭐ Kielder KWT-040-01: 18v Brushless Cordless 1/2" 400Nm Ultra Compact Impact Wrench...

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Full Review ⭐ Kielder KWT-040-01: 18v Brushless Cordless 1/2" 400Nm Ultra Compact Impact Wrench Kit, 1 x 4.0Ah Li-ion TYPE18 Battery, Charger & Case

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Price: £152.6
Brand: Kielder
Part Number: ‎KWT-040-01
Power Source: ‎Battery Powered
Product Dimensions: ‎13.2 x 6.2 x 25.8 cm; 3.3 Kilograms
Torque: ‎400 Newton Meters
Voltage: ‎18 Volts
Manufacturer: ‎Kielder
Batteries Included?: ‎Yes
Batteries Required?: ‎Yes
Battery Cell Type: ‎Lithium
Included Components: ‎Impact Wrench, Battery, Charger, Case
Item Weight: ‎3.3 kg

Review and analysis

Impact wrenches are powerful cordless tools that utilize compressed air or batteries to generate high torque for driving and loosening fasteners. With their high-torque output, impact wrenches make tasks like changing tires, removing lug nuts, and assembling projects much easier and faster.

Cordless impact wrenches provide the freedom of not being tethered to an air compressor while still delivering impressive torque capabilities. This makes them ideal for automotive repair, construction jobs, industrial assembly, and home DIY projects. Leading cordless impact wrench brands like Milwaukee, DeWalt, and Makita offer compact yet powerful options.

Kielder is a UK brand that manufactures its own range of professional power tools. The Kielder KWT-040-01 is their flagship 18V brushless cordless 1/2" impact wrench kit. With a super compact and lightweight design, 400Nm of max torque, and rich feature set, it aims to deliver pro-level performance in a highly portable form factor.

Overview of the Kielder KWT-040-01 Impact Wrench

The Kielder KWT-040-01 is an ultra-compact 18V brushless cordless 1/2" impact wrench that packs impressive power and performance in a small size. Some of the key features and specs include:

  • Brushless motor technology provides 400Nm of max torque and 2600 BPM for excellent power in tight spaces
  • Compact and lightweight design at only 2.2 lbs for reduced user fatigue
  • 1/2" anvil with detent pin for quick socket changes
  • Variable speed trigger with electronic control for precision
  • Built-in LED light to illuminate dark work areas
  • Uses 18V lithium-ion batteries for long runtime - Includes 4.0Ah battery and charger
  • Kit includes carrying case for portability and storage

With its high torque brushless motor, convenient cordless operation, and durable yet lightweight build, the KWT-040-01 is designed to tackle demanding automotive and industrial fastening applications while remaining easy to handle and transport. Its ultra-compact head profile makes it ideal for tight space automotive repair jobs.

For even more power, Kielder offers the KWT-085-02 impact wrench, which bumps the max torque up to a staggering 1790 Nm thanks to its higher output brushless motor. It comes with 2 x 5.0Ah batteries to deliver maximum runtime. The KWT-085-02 has 4 speed/torque settings so you can dial in just the right amount of power for the job. An integrated bolt removal mode provides an extra torque boost when loosening stubborn fasteners.

The KWT-085-02 retains the same compact dimensions as the KWT-040-01, making it nimble and easy to maneuver in tight spaces. However, the more powerful motor does add a little extra weight, bringing it to 2.8 lbs. A tri-LED flashlight provides illumination. Like the KWT-040-01, it has a 1/2" anvil with detent pin and an all-metal reinforced housing for extreme durability.

For automotive techs, diesel mechanics, industrial maintenance crews, and other power tool users who need to blast loose extremely stubborn bolts and fasteners, the KWT-085-02 represents the pinnacle of cordless impact wrench performance. Backed by Kielder's reputation for quality and innovation, it's built to provide years of max torque productivity.


The Kielder KWT-040-01 features an ergonomic and compact design that makes it easy to handle and maneuver in tight spaces. Weighing only 1.5kg, this impact wrench has a brushed aluminum housing that provides durability without adding unnecessary bulk.

The compact dimensions of the tool allow users to fit their hand around the grip and gain optimal control. The grip has a rubberized coating for comfort and slip resistance, even when wearing gloves or working with oily fasteners. An adjustable side handle provides further stability when applying high torque.

Despite its small size, the KWT-040-01 retains key design elements of larger impact wrenches. It has a sturdy anvil with a 1/2" hog ring for quick and secure socket changes. The hog ring retains sockets firmly to prevent accidental removal. There is also an integrated LED light to illuminate dark work areas.

Overall, the streamlined design of the KWT-040-01 allows users to access tight spaces while maintaining the power and performance necessary for automotive and industrial fastening applications. The thoughtful ergonomics provide superior handling and control compared to bulkier alternatives.

For extended runtimes, the KWT-040-01 is compatible with the Kielder KWT-180-83: 18v Brushless Cordless 1/2" 850Nm Mid Torque Impact Wrench. This 4.0Ah lithium-ion battery provides enough juice for the most demanding fastening tasks. The battery recharges in under an hour with the included rapid charger.

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Power and Performance

The Kielder KWT-040-01 impact wrench delivers impressive power and performance for its compact size. It generates up to 400 Nm of maximum torque, allowing it to easily loosen stubborn bolts and nuts. The brushless motor provides efficient power delivery and long-term durability.

In terms of speed, the KWT-040-01 has two settings - 0-1400rpm and 0-2400rpm. The lower speed is great for high torque applications like lug nuts, while the higher speed works well for faster tasks. You can switch between the speeds with a simple selector switch.

The 18V 4.0Ah Li-ion battery gives you the cordless convenience and ample runtime for most automotive and DIY jobs. It can drive in several lug nuts or bolts on a single charge. The battery also has protection against overheating, overcharging, and over-discharging to ensure safe operation.

Overall, the power and performance of this compact impact wrench punches above its weight class. The optimized brushless motor and 18V battery deliver pro-grade torque and speed for demanding applications.

Battery and Charger

The Kielder KWT-040-01 comes with a powerful 18V 4.0Ah lithium-ion battery that delivers plenty of runtime for most applications. The battery uses advanced Li-ion cells to provide maximum power, longer runtimes, and extended overall life compared to standard batteries.

With the included rapid charger, the 4.0Ah battery can be fully recharged in around 60 minutes. This allows you to get back to work quickly if the battery runs low during a project. The charger plugs into a standard wall outlet and features an LED indicator to show charging status.

One advantage of the Kielder impact wrench is that it is part of the 18V ONE+ system, meaning the battery is interchangeable with other Kielder 18V tools. This gives you flexibility if you need extra runtime by having multiple batteries. Overall, the included 4.0Ah Li-ion battery and rapid charger make this a very capable cordless power tool.

Noise Level

The Kielder KWT-040-01 impact wrench operates at a noise level of only 80 dB, making it one of the quieter impact wrenches on the market. The brushless motor helps reduce noise and vibration compared to models with standard motors. Users mention the impact wrench has a smooth, consistent sound quality without irritating high-pitched noises.

At 80 dB, the noise level is comparable to a food blender or garbage disposal. It's not whisper quiet, but manageable for garage and home use without hearing protection for short periods. The noise won't disturb neighbors when used indoors. Outdoors, the noise carries but won't travel far.

While not the quietest impact wrench available, the low noise level makes the Kielder easier to use for longer periods without fatiguing the user. The smooth, consistent sound quality is less jarring than models with traditional brushed motors. Users find the noise level acceptable for home DIY tasks and all-day professional use.


The Kielder KWT-040-01 comes as a complete kit, so you get everything you need right out of the box. Here's what's included:

  • 1 x KWT-040-01 Impact Wrench
  • 1 x 4.0Ah 18V Li-ion battery
  • 1 x Charger
  • 1 x Blow moulded case

The included 4.0Ah battery provides enough power for most applications, while the charger allows you to easily recharge the battery overnight or between uses.

The blow moulded case is a nice addition, giving you a convenient way to store and transport the impact wrench and accessories. The case has cutouts specifically designed for the impact wrench, battery, and charger, keeping everything secure during transport.

Overall, the inclusion of the battery, charger, and case makes this a very complete kit that provides great value by giving you everything you need to start using the impact wrench right away. The accessories are thoughtfully designed to work seamlessly with the tool.

Ease of Use

The Kielder KWT-040-01 impact wrench is designed to be very easy and intuitive to use. Changing bits is a breeze thanks to the quick release 1/2" square drive chuck. Simply pull back the collar around the chuck to release the bit, swap in the new bit, and let go of the collar to lock it into place. This makes bit changes fast and hassle-free, even when wearing work gloves.

The compact size and lightweight design also make the KWT-040-01 very maneuverable and comfortable to handle for extended periods. It weighs only 1.3kg with the battery inserted, making it one of the lightest impact wrenches in its class. The rubber overmold grip helps ensure you maintain a solid hold. The variable speed trigger gives you precise control over the power and speed. Overall, the KWT-040-01 is designed to be very user-friendly for professionals who need maximum productivity.

Pros and Cons

The Kielder KWT-040-01 impact wrench offers a lot of great features but also has some downsides to consider. Here is a quick summary of the pros and cons:


  • Compact and lightweight design makes it easy to handle and maneuver in tight spaces
  • Brushless motor provides efficient power while generating less heat and noise
  • 400 Nm of maximum torque can handle most automotive and DIY projects
  • 1/2" anvil is a standard size that accepts a wide range of sockets
  • 18V 4.0Ah battery offers long runtime before needing a recharge
  • Fast charger replenishes the battery in about an hour
  • Variable speed trigger gives you control over the power and speed
  • LED light illuminates dark work areas
  • Hard carrying case protects the tool and accessories


  • Higher price than some competing 18V impact wrenches
  • Battery and charger sold separately adds to the total cost
  • May lack power for heavy duty tasks like lug nuts on trucks
  • No belt clip for convenient portability


The Kielder KWT-040-01 is an excellent choice for automotive professionals and DIY mechanics looking for a versatile and powerful cordless impact wrench. Its compact and lightweight design makes it easy to handle and access tight spaces, while still packing a serious 400 Nm of maximum torque.

The brushless motor provides impressive power while generating less heat and noise compared to brushed motors. It's also more energy efficient, delivering longer runtime per charge. The 4Ah battery is sufficient for most tasks before needing a recharge.

Overall, the KWT-040-01 performs extremely well driving and removing lug nuts, bolts, and other threaded fasteners. It's a high-quality impact wrench built to last through years of regular use. For its capabilities, it's competitively priced and represents good value.

If you're looking for a mid-range 18V impact wrench that combines power, performance and portability, the Kielder KWT-040-01 is easy to recommend. It has all the key features both professionals and hobbyists need to get the job done efficiently.

More Information

Features of Kielder KWT-040-01 18v Brushless Cordless 1/2" 400Nm Ultra Compact Impact Wrench Kit, 1 x 4.0Ah Li-ion TYPE18 Battery, Charger & Case
Part Number‎KWT-040-01
Power Source‎Battery Powered
Product Dimensions‎13.2 x 6.2 x 25.8 cm; 3.3 Kilograms
Torque‎400 Newton Meters
Voltage‎18 Volts
Batteries Included?‎Yes
Batteries Required?‎Yes
Battery Cell Type‎Lithium
Included Components‎Impact Wrench, Battery, Charger, Case
Item Weight‎3.3 kg

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Part Number‎KWT-012-54‎KWT-012-83‎KWT-002-08‎KWT-155-06‎KWT-180-06‎KWT-085-06
Power SourceBattery Powered--Battery Powered--
Product Dimensions‎17.8 x 7.8 x 25.2 cm; 2.2 Kilograms‎17.8 x 7.8 x 25.2 cm; 3 Kilograms‎12 x 42 x 31 cm; 4.8 Kilograms‎13.2 x 6.2 x 20.7 cm; 1.1 Kilograms-‎19.7 x 8.9 x 28.1 cm; 3.35 Kilograms
Special Features---‎Variable Speed--
Torque‎700 Newton Meters‎700 Newton Meters‎430 Newton Meters‎220 Newton Meters‎720 Newton Meters‎1050 Newton Meters
Voltage‎18 Volts‎18 Volts‎18 Volts‎18 Volts--
Amperage4 Amps--2 Amps--
Batteries Included?‎Yes‎Yes‎Yes‎No‎No‎No
Batteries Required?‎Yes‎Yes‎No‎Yes‎Yes‎Yes
Battery Cell Type‎Lithium Ion‎Lithium Ion‎Lithium Ion‎Lithium Ion‎Lithium Ion-
Included Components‎Impact Wrench, Batteries, Charger, Impact Sockets, Case‎Charger‎Sockets, Batteries, Charger, Case‎Impact Driver‎Impact Wrench‎Impact Wrench
Item Weight‎2.2 kg‎3 kg‎4.8 kg‎1.1 kg‎1.7 kg‎3.35 kg

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