1.The lock is made of pure-copper or stainless steel and is very durable; 2.Dissociative knob which prevents external press from destroying; 3.Coming by solt-fog experiment that last over 600 hours; Use Siemens encryption techniques which is counterfeit-preventing; 4. Realizing the parent-card management: use the parent card to add or delete the electric keys; 5.Door-unlock-warning: this can warn the user and ensure100% security. 6.New-type lock barrel with smaller size and backlocking; Static function: d2F; 7.Can register 255 exclusive user cards and support offline network function.