This is a plain back patio door roller assembly with a 1-1/4 in. concave steel ball bearing roller. It has a unique plain back housing that is 13/16 in. wide with a 31/32 in. flare and 1-5/32 in. tall. It is rear adjusting with a 0.228 diameter mounting hole on the back end. It is used by Acorn, Wells Aluminum and a variety of manufacturers of sliding patio doors.