Two lock-prep options are available for single door models: (1) The cylindrical lock prep is government 161 with 2-3/4" backset. (2) The 86 mortise lock prep has a 2-3/4" backset trim cutout. Locking mechanisms preserve the safe fire-rating of the door. Preps can be placed on left- or right-hand sides (specify at time of order).
One lock-prep option is available for double door models. Double doors come with cylindrical-lock preps for installation of desired handles. The 1.75"-thick doors are left-hand reverse (LHR), with the doors opening out from the room.