iFingerLock Fingerprint Biometric Padlock ($84.99) Your fingers are your keys! Just slide your finger to unlock instantly! Semiconductor slide sensor-based fingerprints or biometrics recognition technology. Super large 10-fingerprint storage, allowing up to 10 users to use the lock (one administrator and another 9 persons). No computer needed. Indoor use only. Powered by 2 AAA batteries. The lock retains all stored fingerprints even out of battery.