The double bitted model comes with an innovative, patented system of recoding through a metallic “SIM”. You can replace the coding card of the key (from the internal side of the door), without the need of a screwdriver and without replacing the escutcheon. An extremely easy, quick and “self-made” system that will allow anybody, at any time, to change the combination of the lock, when needed and without calling any expert. The gear mechanism assures a silent and soft operation. The lock is protected by a manganese shield. A KA testing key is supplied.