【0.2s Big Biometric Fingerprint】 : This Fingerprint Combination Door Knob has 4 ways to open the lock. 255 Biometric fingerprint, APP, Keypad unlock, eliminating the worry of forgetting your keys. And 2 spare keys in case the batteries die. A variety of unlocking methods bring more convenience to your life. 【Easy to Program Fingerprint Lock】 : A single administrator user can operate all functions. Disguise your password using up to 20 numbers to prevent snoopers. Turn on "Passage Mode" to allow temporary users to enter and exit easily. If you don't want others to hear any sound feedback, turn on "Silent Mode". After closing the door, the lock will "Auto Lock" after 3 seconds. And you can unlock it with one click through the app. You can also check the unlock record and power. 【Back Locking, Privacy Protecting】High-quality metal surfaces and robust zinc alloy construction enhance safety and service life. When the back locking is turned on, neither the key nor the code nor the fingerprint can unlock it, enhancing the privacy of your space and protecting your personal assets, keeping your children away from the bad guys. 【Easy Installation, Takes Only 5 Minutes】This fingerprint Combination lock is applicable to most American interior standard doors. Adjustable Latch 2-3/8″(60mm) and 2-1/8″(70mm). The door thickness between (1.26~1.89inch). The same brand of 4 x AA alkaline battery is required to provide up to one year of battery life. If there is no power in special circumstances, you can use the USB interface directly below to charge and unlock. 【Ideal for Multiple Spaces】 Great for upgrading door knobs in offices, dormitories, storage rooms, laundry rooms, bedrooms, and more, with a 30-day money-back guarantee, 1-year replacement warranty, and 24/7 customer support for any questions. Fingerprint Smart Door Knob, Keyless Entry Door Lock, 4 Unlocking (Fingerprint/Keypade/App/Key), Back Locking Biometric Door Knob, for Bedroom, Office, Hotel