... .vending machine lock and key 2.Material: Zinc,Stainless Steel 3.Key changes: More than 10,000.Master Key system ... cabinet, Vending Machine, ATM and etc.1.4 Key changes: More than 10,000.Master Key system is available ... 1.6 Accessories: nut..........As pictured above, key B could unlock all the locks in system B ... system B and system C. This Master Key system could solve the problems of lock management ...