SD is Special cylinder dogging in the center case of 98/99 rim and vertical rod non fire rated devices and is available with standard, EL, QEL, CX and ALK.
Special Dogging can be added but you will need a new center case assembly, cylinder dog housing, and center case cover.
050550, SD center case kit RHR and 050551, SD center case kit LHR.
112409...
There is not enough room for both options as the dogging mechanism in a standard cylinder dogging and the electronics for the EL or QEL options are both located at the end of the base plate.
For 9...