Danalock Bluetooth Low Energy Smart Lock, Retrofit Your Existing Deadbolt, Compatible with iOS and Android 4.4, Bronze Invite: send unlimited keys to family, friends, and visitors with either full or limited access Secure: patented, highest level of encrypted security available Retrofit: install danalock, inside your home, over your existing deadbolt with everyday tools Keyless or Key: operate by app, hand, press of a button or use your traditional key. Monitor: detail log of all lock activities via your smartphone or web browser