Features: 1) Adopts highly reliable microcomputer control system 2) High security level 3) 9102DG model has ten groups of separate passwords (maximum 3,000 groups after extension) 4) Each group of passwords can be controlled separately, such as startup, prohibiting, setting and changing passwords 5) Password can be changed by owner 6) Password recover: when all the passwords are lost or forgotten, the lock can be recovered to the factory status without affecting the locks security