Standard mortise applications require use of BEST's 1E series cylinders with standard 1E-C4 cam. BEST cylinders may be altered to function with other manufacturers' locks by use of different cams and different cylinder rings. Special cylinder variations are available for most applications. Additional security is provided by a set screw that mounts diagonally in the cylinder wall and when tightened, holds the cylinder securely in the housing. BEST mortise cylinders feature the BEST interchangeable core and may be master-keyed into any existing BEST system. This 1E series standard mortise cylinder has a 7 pin, small format, interchangeable core housing; core must be purchased separately.