Interchangeable cores for locks were invented to allow for quick keying and re-keying of locks. There are two styles of interchangeable cores, the Small Format Interchangeable Core (SFIC) and the Full Size Interchangeable Core (FSIC). Both are recognizable by their figure 8 shape. The SFIC cores are smaller than the FSIC cores.The convenience of these cores is in the interchangeability. Conventional cores require the removal of parts on the locks to install or replace. Interchangeable cores are installed and removed with the use of a special key called a control key. The control key retracts a piece of the core (such as a pin or bar) that holds the core in place. When the core is inserted and the key is removed, that small piece will be held secure inside the housing. The housing must be compatible with that small small piece on the core.


SFIC cores have been around lounger than the FSIC. BEST is the first brand to invent the SFIC core back in the early 1900’s. Since then many brands can match the BEST core prep. FSIC cores, on the other hand, are often specific to each manufacturer allowing for more security and control. However, many brands can prepare their locks to receive competitor FSIC cores (i.e. Schlage can prep their locks to receive FSIC cores from ASSA).

Talk with a Beacon CDL sales rep to discuss options to re-key your building.