- 100% mechanical operation, no batteries or external power supply required, it is waterproof. - Unlock by button code(without key or card), change the code on the back of the lock box before, the password for unlocking has no sequence. If the password is set to 12345678, the password 87654321 can also unlock, always press the "C" key before entering the code to open the lock - Suitable for left-open door and right-open door, the handle direction can be changed accordingly, suitable for door thickness: 35mm to 60mm - Easy to install, after making holes on the door according to the attached template. NOTE: Please make sure all parts are working properly before installation. Do not overtighten the mounting bolts, as this may cause distortion and stress in the event of malfunction. Do not close the door until the code and locking work have been previously confirmed.