This is a plain back patio door roller assembly with a 1-1/4 in. concave or grooved steel ball bearing roller. It has a plain back housing that is 11/16 in. wide and 1-1/4 in. tall with a flare width of 13/16 in. with a rear adjusting screw. Features a 1/4-20 machine thread mounting hole on the plain back end and a 10-32 threaded optional use hole on the top. Used by Blomberg and a variety of other manufacturers of vinyl and metal sliding patio doors.