Dorex DM70 Heavy-Duty Mortise Lockset – Classroom Function – Satin ChromeDM70 SS 26D Classroom function suitable for doors that need to remain locked or unlocked for lengthy or specific periods Architectural quality for heavy duty commercial and institutional applications High quality satin chrome finish For 1 3 4 2 door thickness conversion kit available for doors up to 2 1 4 thick 2 3 4 backset Handed field reversible Thru bolt mounting sectional trim with concealed mounting screws 2 7 16 diameter rose Lever length is