The lock is made of pure-copper or stainless steel; Dissociative knob which prevents external destroying press; Coming by solt-fog experiment that last over 600 hours; Use Siemens encryption techniques which is counterfeit-preventing; To Realize the parent-card management: use the parent card to add or delete the electric key;New-type lock barrel with smaller size and backlocking;Static function: d2F;Can register 255 exclusive user cards and support offline network function.