Split key systems are delivered in the highest level section on the key tip (insert):
L - obverse or classic
Y - reverse
0000 - Paracentric
ZZZZ - Quad
D000 - restricted Everest
C000 - open...
It is not possible to key SFIC and standard cylinders including Schlage FSIC into the same system. A keyway name may be shared between the two key fami...