Fingerprint sensor allows you to lock and unlock the door with a single tap to the touchscreen keypad 6-8 digit access codes can be entered on the keypad and customized for each family member Companion app for iOS and Android devices make it easy to remotely lock and unlock the door, as well as track unlock history by user Runs on four AA batteries (included) and comes with backup physical keys in case of power failure Auto lock feature conveniently locks the door by itself Instant battery charging terminal lets you open the door with a 9V battery (sold separately) if you forget to replace dead batteries Matte black finish complements your existing hardware Note: Not recommended for outdoor use where exposed to direct rain