Mul-t-lock Hercular Single Cylinder deadbolt w/Thumb turn - Bright Brass High Security deadbolt system for commercial and residential doors. 90 key rotation throws the bolt 1" towards the frame, interlocking two hardened ball bearings with the strike to increase jimmying resistance. Adjustable backset 2-3/8 or 2-3/4 , no need for different parts Bright Brass US3 Finish Interative+ Key System, Locks Supplied Keyed Different with 2 keys - Control Card Required for Duplicate Keys