This is a plain back patio door roller assembly with a 1-1/2 in. concave steel ball bearing roller. It has a plain back housing that is 3/4 in. wide with a 27/32 in. flare, and is 1-9/16 in. tall. It features a rear adjusting screw with a 1/4-20 threaded mounting hole on the back end. A variety of sliding patio door manufacturers use this roller assembly.