Smart Fingerprint Chain Lock with Electronic Key Child & Pet Safety Window Restrictor 1. This product utilizes semiconductor biometric technology, suitable for various scenarios including windows, refrigerators, doors, cabinets, washing machines, and file cabinets. It supports both non-drillingdrilling installation modes, can manage up to 20 fingerprints, and meets home and office security needs. 2. Semiconductor Biometric Technology effectively resists fake fingerprints, enables 1-second recognition, and provides keyless unlocking. 3. Reinforced aluminum alloy chain link ensures robust durability and resists forced opening. 4. Long Battery Life & Convenient Charging: Low-power design allows for approximately 10 months of use with 5 unlocks per day. Features USB-C fast charging for immediate use after charging. 5. The product comes with an electronic key for configuring fingerprints, adding new entries, and restoring factory settings. 6. Material: ABS + Aluminum Alloy 7. Chain Length: 24.5cm; Max spacing: 17.5cm 8. Operating Voltage: 3.5V - 4.2V