Various Access : YDM 4109 has multiple options to access the lock- Fingerprint, Pin Code, Key Override, Bluetooth (via Yale Link app). Peace of mind, anytime : Yale is where you are. Lock, unlock, share access, see who comes and goes using your Yale app - anywhere, anytime. With Yale App and Wifi-bridge you can lock or unlock your door, share keys with family and friends, get notifications when someone comes home and more, all from one mobile app. Convenience: It can upgrade your existing door lock and supports door thickness from 40 mm to 80 mm. No wires, no hassle and easy to replace, with 4 x AA batteries and a warning when they are running low. The lock’s memory will also ensure all credentials and settings remain when changing the batteries, making this simple and hassle free. Automatic Locking: Auto-Lock automatically secures your front door once it’s closed. Enjoy peace-of-mind never worrying if your door is locked. Low battery alarm and emergency power supply terminal : It warns in case of low battery with alarm and LED. When the batteries are completely discharged, you can easily supply emergency power to the lock with a standard 9V battery. Connectivity: Wire less connectivity with Video Door Phones ( Separate Accessories required) Warranty: 3 years from the date of purchase