Intructions:Material - stainless steelSupported OS - iOS 7.0 or later, Android 4.4 or laterBattery Life - Can provide 5000 unlocks (in approx. 6 months)Power Supply - 4 pcs of 1.5V AA Alkaline BatteriesUnlock Mode - APP, Fingerprint, Code, M1 Card, Mechanical KeyWorking Temperature - 0~80°CHow to select the lock?1.Check door thickness: 35~55mm (if over 55mm, pls contract us)2. Measure your old door lock like the picture below, then choose the most suitable mortise size.3. Judge your door lock direction, then leave a note of the order.DoorbellUSB PortTimed PasswordDynamic PasswordFree HandleLow Battery Alarm