Fortress locks have over 200,000 different lock combinations. Besides the standard lock (CL) it is also possible to have a master series (ML) which can be operated by as special cut master key (MLK-SUGS) that fits any mastered lock in a specific mastered lock series. For each of use all Fortress locks provide key insertion in two directions.

The MLIS lock is standard supplied with a stainless steel dustcover.

Each different key combination is allocated with an engraved code onto the lock and key, of up to maximum 30 characters (3 lines of 10 characters), this engraving code is used to identify locks and keys and is recorded in a database for continuous cross reference. Required engravings are therefore to be provided with each order.