KEYLESS - Gives you the freedom to secure your home without the need for a Key. SIMPLE TO FIT - Suitable for most PVC and composite doors, only a screwdriver required. BATTERY POWERED - 4x AA batteries Included and an Alert given when the batteries are running low. BSI APPROVED - The world first BSI approved smart lock. SECURITY AS STANDARD - Built in tamper alarm, bank level encryption and incorrect pin code features. Note: Suitable for doors with a thickness of between 44-70mm.