Locks that relied on biometric identification were once in the realm of science fiction. Now they are firmly in the realm of science fact.  Biometric Locks  are used in a wide number of applications in this day and age. They may be used in retail for safeguarding inventories, in banks for ensuring only certain people have access to vaults or even homes to allow only certain people in to some rooms or to keep some items like guns for instance, out of the reach of children and unauthorized persons. They can be used almost everywhere where one can expect to use normal sorts of locks. They are now generally quite affordable to own and operate.