http://www.cndigiper.com 1. pure stainless steel mechanical rotating struture enable for using more than 10 years. 2. it is very easy to change batteries in the lock,just need several minutes on one lock. 3. using 4 x 1.5v standard alkaline batteries. 4. unlock ways: fingerprint or keypad or mechanical key. 5. can de-lete the users individually who were fired.but there is no effect for the other people to use. 6. if the fingerprint is not input correctly. the handle is free handle; it can provide the door from opening by fore, and prolong the using of the mechanism of the lock. 7. fingerprint user capacity 150. 8. especialy suitable for installation by non-professionals.