Introduction
This manual provides comprehensive instructions for the installation, operation, and maintenance of your Kadonio 408 Plus Smart Door Lock. Designed for main entrance doors, this lock offers multiple unlocking methods including fingerprint, mechanical key, and mobile application control. Please read this manual thoroughly before installation and use to ensure proper function and longevity of your device.

Figure 1: Kadonio 408 Plus Smart Door Lock featuring fingerprint and key unlock.
Specifications
| Feature | Detail |
|---|---|
| Model Number | 408 Plus |
| Brand Name | Kadonio |
| Ways To Unlock | Fingerprint, Key, APP (Tuya Smart Bluetooth) |
| Door Type Compatibility | Wood door, Steel door, Stainless Steel door, Aluminum door, Brass door |
| Door Thickness | 35-55mm |
| Mortise | 4585 / 22*240 mm |
| Material | Aluminum Alloy |
| Power Supply | 4pcs AAA Alkaline Battery |
| Fingerprint Capacity | Up to 30 fingerprints |
| Working Temperature | -20℃ to +55℃ |
| Features | Emergency USB backup power, Normal Open Mode, Left and right universal handle |
| Certification | CE, FCC, ROHS, ISO9001 |

Figure 2: Detailed dimensions and mortise specifications (22x240mm) for the lock.
Setup and Installation
The Kadonio 408 Plus Smart Door Lock is designed for easy installation and can directly replace spherical keyholes, provided the panel width is 65mm or less.
Door Compatibility:
- Compatible with Wood, Steel, Stainless Steel, Aluminum, and Brass doors.
- Suitable for door thicknesses between 35mm and 55mm.
- The handle design is universal for both left-handed and right-handed doors.

Figure 3: The lock can directly replace spherical keyholes with a panel width of 65mm or less.

Figure 4: The handle is designed to be universal for both left and right opening doors.
Battery Installation:
- The lock requires 4 AAA alkaline batteries for power.
- Ensure batteries are inserted with correct polarity.
- Batteries are the sole power source for the lock.

Figure 5: Battery compartment for 4 AAA batteries and the USB emergency power port.
Operating Instructions
Your Kadonio 408 Plus Smart Door Lock offers multiple convenient ways to unlock your door.
1. Fingerprint Unlocking:
- The lock features 360° fingerprint recognition for quick identification.
- Place your registered finger on the sensor. The lock will unlock in approximately 0.5 seconds.
- The lock can store up to 30 unique fingerprints.

Figure 6: Fingerprint unlocking mechanism with quick 0.5s recognition.
2. Mechanical Key Unlocking:
- For traditional access or in case of emergency, use the provided mechanical key.
- Insert the key into the keyhole located on the lower part of the exterior handle.
- Turn the key to unlock the door.
3. Mobile APP Unlocking (Tuya Smart Bluetooth):
- Download the Tuya Smart app on your smartphone.
- Connect your phone to the lock via Bluetooth.
- Use the app for lock management, including unlocking the door remotely.
- For WiFi connectivity and extended remote control, a Tuya Gateway is required.

Figure 7: Mobile APP unlocking process and network setup with Tuya Gateway.
4. Normal Open Mode:
- This mode allows the door to be opened freely without requiring authentication.
- It is convenient for periods of high traffic or when children and elderly need easy access.
- Refer to the app or specific lock settings for activating and deactivating this mode.

Figure 8: Normal Open Mode allows unrestricted access, ideal for convenience.
Video 1: Demonstration of fingerprint, key, and app unlocking methods, along with normal open mode.
Maintenance
Battery Replacement:
- The 4 AAA alkaline batteries should be replaced every 8-12 months to ensure optimal performance.
- Low battery warnings will typically be indicated by the lock.
- Always use new, high-quality alkaline batteries.
Cleaning:
- Wipe the lock's exterior with a soft, dry cloth.
- Avoid using abrasive cleaners or solvents, as these can damage the finish and electronic components.
Troubleshooting
Emergency Power Supply:
- If the batteries run out completely, the lock can be temporarily powered using a power bank connected to the emergency USB backup power port.
- This port is for emergency power supply only; DO NOT attempt to charge internal batteries through this port.
- Always keep a mechanical key accessible for backup.
Fingerprint Not Recognized:
- Ensure your finger is clean and dry.
- Try repositioning your finger on the sensor.
- If issues persist, re-register your fingerprint through the Tuya Smart app.
App Connectivity Issues:
- Ensure Bluetooth is enabled on your smartphone and the lock is within range.
- Restart the Tuya Smart app.
- Check if the lock's batteries are low.
- If using a Tuya Gateway for WiFi, ensure the gateway is properly configured and connected to the internet.
User Tips
- Register Multiple Fingerprints: For convenience and backup, register fingerprints for all regular users and consider registering multiple angles of your primary finger.
- Keep Emergency Key Safe: Store the mechanical backup key in a secure location outside your home, accessible in case of electronic failure or dead batteries.
- Monitor Battery Life: Pay attention to low battery indicators and replace batteries proactively to avoid being locked out.
- Utilize Normal Open Mode: For gatherings or when you need frequent access, activate the Normal Open Mode via the app to temporarily disable authentication.
- Regular App Updates: Keep your Tuya Smart app updated to benefit from the latest features and security enhancements.
Warranty and Support
The Kadonio 408 Plus Smart Door Lock comes with a 1-year warranty from the date of purchase. This warranty covers manufacturing defects and malfunctions under normal use. Please retain your proof of purchase for warranty claims.
For technical support, troubleshooting assistance, or warranty inquiries, please contact the seller or manufacturer directly. The manufacturer, Botin Smart Technology (Guangdong) Co., Ltd., has over 16 years of manufacturing experience and offers dedicated after-sales service.
Contact information for support can typically be found on the product packaging or the seller's official store page.