Used to install HES 5200 x 501A SERIES 4-7/8" ASA electric strikes. Faceplate size 1-1/4" x 4-7/8". Mounts to door or frame with self-drilling screws (supplied). Requires the use of a router equipped with a 3/8" outside diameter template guide and a 1/4" diameter router bit. For use on offset hung aluminum doors and frames only.