1. Introduction
This manual provides essential information for the safe and effective use of your Seesii 3/8'' 80Nm Cordless Electric Ratchet Wrench, Model RT800B. This tool is designed for professional fastening and drilling applications, particularly useful for driving fasteners in wood and metal. Its extended neck, powerful brushless motor, and variable speed control make it an efficient tool for various tasks, including auto repair and general assembly.
Please read this instruction manual thoroughly before operating the tool to ensure safe usage, optimal performance, and to prevent injury or damage.
2. Safety Information
WARNING: Read all safety warnings and instructions. Failure to follow the warnings and instructions may result in electric shock, fire, and/or serious injury. Save all warnings and instructions for future reference.
2.1 General Power Tool Safety Warnings
- Work Area Safety: Keep work area clean and well lit. Do not operate power tools in explosive atmospheres. Keep children and bystanders away.
- Electrical Safety: Power tool plugs must match the outlet. Avoid body contact with earthed surfaces. Do not expose power tools to rain or wet conditions. Do not abuse the cord. Use an extension cord suitable for outdoor use when operating outdoors.
- Personal Safety: Stay alert and use common sense. Use personal protective equipment, including eye protection. Prevent unintentional starting. Remove adjusting keys/wrenches before turning on. Do not overreach. Dress properly. Use dust extraction facilities if provided.
- Power Tool Use and Care: Do not force the power tool. Use the correct power tool for your application. Do not use the power tool if the switch does not turn it on and off. Disconnect power before making adjustments or storing. Store idle tools out of reach of children. Maintain tools and accessories. Keep cutting tools sharp. Use tool, accessories, and bits according to instructions.
2.2 Battery Tool Use and Care
- Recharge only with the charger specified by the manufacturer.
- Use power tools only with specifically designated battery packs.
- When battery pack is not in use, keep it away from other metal objects.
- Under abusive conditions, liquid may be ejected from the battery; avoid contact.
- Do not use a battery pack or tool that is damaged or modified.
- Do not expose a battery pack or tool to fire or excessive temperature (above 130°C).
- Follow all charging instructions and do not charge outside specified temperature range.
2.3 Driver Safety Warnings
- Hold the power tool by insulated gripping surfaces when performing an operation where the fastener may contact hidden wiring.
- Wear ear protectors during use.
- WARNING: This ratchet wrench is NOT a torque wrench. Do not use this tool for tightening fasteners to specified torques. An independent, calibrated torque measurement device should be used.
- Wear safety goggles or other eye protection.
- Do not operate this tool for long periods of time. Vibration may be harmful to hands and arms. Use gloves and take rest periods.
- Accessories and tools get hot during operation. Wear gloves.
2.4 Additional Safety Information
- Never modify the power tool or any part of it.
- Always use safety glasses and a dust mask.
- Some dust created by power sanding, sawing, grinding, drilling, and other construction activities contains chemicals known to cause cancer, birth defects, or other reproductive harm. Work in a well-ventilated area and use approved safety equipment.
- Wear protective clothing and wash exposed areas.
- Use appropriate dust extractor vacuum.
- Use clamps or other practical ways to secure the workpiece.
- Avoid loose clothes, jewelry, or long hair near air vents.
3. Package Contents
Please check the package contents to ensure all items are present and undamaged:
- 1 x Seesii 3/8'' 80Nm Cordless Electric Ratchet Wrench
- 2 x 21V Li-ion Batteries (2.0Ah)
- 1 x Battery Charger
- 8 x 3/8" Sockets (10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm)
- 1 x 1/4" Socket Adapter
- 1 x 1/2" Socket Adapter
- 1 x 3" Extension Bar
- 1 x Tool Bag
- 1 x Instruction Manual (this document)

Figure 1: Seesii Cordless Electric Ratchet Wrench and included accessories.
4. Specifications
4.1 Product Specifications (Model: RT800B)
| Feature | Specification |
|---|---|
| Voltage | 21V (Max) |
| Square Drive | 3/8" (9.525mm) |
| Max Torque | 80N.m (59Ft-lbs) |
| No Load Speed | 0-400/min (RPM) |
| Motor Type | Brushless |
| Weight | 2200g |
4.2 Charger Specifications (Model: HC1610-2100750U)
| Feature | Specification |
|---|---|
| Input | 100-240V~50/60Hz 0.8A |
| Output | 21V --- 0.75A |
4.3 Battery Specifications (Model: T1820-5)
| Feature | Specification |
|---|---|
| Voltage | 21V (Max) |
| Capacity | 2000mAh |
| Watt Hours | 37Wh |
5. Setup
5.1 Installing or Removing Battery Cartridge
CAUTION: Always switch off the tool before installing or removing the battery cartridge. Hold the tool and battery cartridge firmly to prevent slipping and potential injury.
- To Insert: Slide the battery pack into the tool body until it latches securely into place.
- To Remove: Push in the release buttons on the battery pack and pull the battery pack away from the tool.
5.2 Charging the Battery
The battery pack must be charged prior to first use. A full charge takes approximately 70 minutes.
- Align the charging cable with the battery.
- Connect the battery to the charger.
- Plug the charger into a power outlet.
- The indicator light on the charger will be Red while charging and turn Green when fully charged.
- Important: Charge batteries at an ambient temperature between 18°C-24°C (65°F-75°F). Do not charge below 4.5°C (40°F) or above 40°C (104°F).
5.3 Installing Impact Socket
CAUTION: Ensure the impact socket and mounting portion are not damaged. After inserting, ensure it is firmly secured.
- Select the Correct Impact Socket: Always use the correct size impact socket for bolts and nuts. Incorrect sizes can lead to inaccurate fastening torque or damage.
- Attach Socket: Align the accessory with the 3/8" square drive anvil and push it firmly onto the tool.
- Remove Socket: Pull the accessory off the drive anvil.

Figure 2: Socket and adapter accessories.
6. Operating the Wrench
6.1 Switch Action (Variable Speed Trigger)
The tool features a variable speed trigger for precise control:
- To start the tool, simply pull the switch trigger.
- Tool speed increases with more pressure on the trigger.
- Release the switch trigger to stop the tool.
6.2 Lock Switch
To prevent unintentional starting, use the lock switch:
- Press the button to engage the lock, preventing the trigger from being pulled.
- Disengage the lock before operating the tool.
6.3 Reversing Switch Action
CAUTION: Use the reversing switch only after the tool comes to a complete stop. Changing direction while the tool is running may damage it.
- The forward/reverse switch allows you to change the rotation direction for tightening or loosening fasteners.
- Push the switch to the 'F' position for forward rotation (tightening).
- Push the switch to the 'R' position for reverse rotation (loosening).

Figure 3: Forward and Reverse Rotation Modes.
6.4 Battery Indicator
The integrated power indicator shows the remaining battery life at a glance, helping you manage your work efficiently.
6.5 Usage Examples
- Tight Spaces: The extended neck and slim head design allow effortless access to frustratingly tight spaces, making it ideal for automotive work or furniture assembly where clearance is limited.
- Assembly Tasks: Use the variable speed trigger to start nuts slowly and then speed up for quick tightening, making assembly of shelving units or other structures efficient.
- Auto Repair: The powerful brushless motor and 80Nm torque make removing or installing nuts on vehicle components effortless, reducing fatigue compared to manual wrenches.

Figure 4: Extended ratchet head for improved accessibility.

Figure 5: Built-in LED light for dark work areas.
Video 1: Product demonstration showing battery installation, socket attachment, and use in various assembly and repair tasks.
7. Maintenance
CAUTION: Always ensure the tool is switched off and the battery cartridge is removed before performing any inspection or maintenance.
7.1 Cleaning
- Wipe the tool with a dry cloth. Do not use water, gasoline, benzine, thinner, alcohol, or other chemical cleaners, as these can cause discoloration, deformation, or cracks.
- Keep the motor vents clean and free from dust.
7.2 Storage
- Store the tool in dry conditions.
- For battery packs, store them below 26°C (79°F) with a 30%-50% charge.
- Charge the battery pack fully at least once every 6 months to prolong its service life.
8. Troubleshooting
8.1 Tool Won't Start
- Verify that the battery is properly installed and fully charged.
- Check the status of the switch lock button; ensure it is disengaged.
- If the tool has been used continuously for too long, it may have overheated. Discontinue use and allow the tool to cool down before continuing.
8.2 Low Power or Slow Operation
- Check the battery level and replace or recharge if necessary.
- Clean any dust and debris from inside and outside the tool to prevent clogging.
- Verify proper operating mode and torque settings for your task.
8.3 Battery Not Charging
- Ensure the original charger is used.
- Check that the charging port is clean and undamaged.
- Confirm the charging indicator shows the charging status (Red light).
8.4 Abnormal Noise or Vibration
- Make sure all components are tight and not loose.
- Check for foreign objects inside the tool and remove any obstructions.
9. User Tips
- Accessibility: The extended neck design is particularly useful for reaching fasteners in confined or hard-to-access areas, making tasks quicker and less strenuous.
- Replacement Parts: For replacement batteries or other parts, it is recommended to contact Seesii customer support directly to ensure compatibility and maintain warranty.
10. Warranty and Support
10.1 Three-Year Warranty Policy
Seesii warrants this Ratchet Wrench to be free from defects in workmanship and materials for a period of THREE YEARS from the date of original purchase. If any issues arise due to defective workmanship or material, Seesii will repair the tool without charge.
This Warranty Does Not Apply Where:
- Repairs have been made or attempted by others.
- Repairs are required due to normal wear and tear.
- The tool has been abused, misused, or improperly maintained.
- Alterations have been made to the tool.
10.2 Customer Support
If you have any issues with your product, require technical support, or need assistance with warranty claims, please contact us:
Email: support@seesiius.com
Manufacturer: Ningbo Goodo Tools Co., Ltd.
Address: Second floor, Building 3, No.168 Tonghe East Road, Luotuo Subdistrict, Zhenhai District, Ningbo, CHINA