Read more Backup Key Unlock in Emergency Harfo fingerprint lock features a hidden key hole for accessing the door with physical keys as backups in case of emergency access. Just press the cap of the outer lock to pry up the cap, insert the key and turn 90 degree to open door. 300 Users for Your Needs The lock can store 300 users include fingerprint, passcode and Ic cards.You can generate one-timed passcode for your guests and housekeepers! The Casual user password will be invalid after once used. Fit for Left & Right Door This smart deadbolts suit for both left & right door. You just need to adjust the rotary knob and “L/R Button” for left or right door opening. Read more Auto Lock Function Never forget to lock on the way out. Auto-lock will lock it for you. You can set the auto-lock time from 5s/10s/15s/20s according your needs. Anti Peeping Password As long as we enter correct password continuously. We can enter numbers randomly before and after the correct password to prevent others from knowing the correct password. Easy DIY Installation Easy to install. Just follow the user manual to finish the assembling even you are not a professional. The suitable door thickness range for the door lock is 1 3/8 inch to 2 3/16 inch 35mm-55mm thick. Read more No APP/WIFI Needed No app/wifi needed, no complicated setting. The front door lock sets are easy to use with function oled display & voice guide, suitable for your family to use together. Strong and Durable Strong and solid build, made of Zinc alloy. Suitable for any season. Its working environment temperature is -4 °F to 140 °F. Powerbank Compatible if you miss the low battery alarms, there is a usb power port under the lock, please use a powerbank to power it up via a small power port and get door unlock. Read more Read more