This lock and door reinforcer is constructed of stainless steel and fits 1-3/4 in. thick doors. Assists in preventing forced entry by reinforcing the weak spot of an entry door and it can be used on both metal and wood doors. Accommodates key-in knob locksets on doors that have a backset of 2-3/4 in. These door reinforcers are easy to install and they are used by many. All installation fasteners are included with this item. This guard features a 2-1/8in bore 2-3/4in backset 1-3/4in door thickness 3-7/8in width 9in height.