Features: 1. No lock hole design, it completely abandons the traditional key and lock, open and close by remote control( RC without Batter y ). 2. It can be locked and unlocked inside by touching the lock body. 3. USB external power source function, Make sure that the lock works when the battery is empty. ( Battery not include d ) 4. Four optional unlocking modes: Unlocking phone APP, unlocking remote control, unlocking indoor button, unlocking indoor touching. 5. More stable and secure. Easy installation on all types of doors, very convenient. Specification: Lock: Power Supply: 2x AA batteries(not included) Transmission Frequency: 433MHz(500KHz) Operation Range: Within 20m Unlocking Mode: APP unlocking&Remote control unlocking& indoor button/touching unlocking Size: 15.5x8x3.5cm Remote Controller: Battery(Each): 1x 3V battery Standard Number: 4 (included) Max Controller Number: 16 (not included) Function: Lock &unlocking Size(Each): 6x3x1cm Package Includes: 1x Lock 1x Lock Body Bracket 1x lock 4x remote key 1x USB power cable 1x BT adapter 1 bag x screwsincludes:1x Lock 1x Lock Body Bracket 1x lock 4x remote key 1x USB power cable 1x BT adapter 1 bag x screws