This is an unique back diecast patio door roller assembly with a 1-1/4 in. concave steel ball bearing roller used on Crossly doors. It's unique diecast housing is 11/16 in. stepping down to 9/16 in. wide, 1-1/8 in. tall and 2-5/16 in. long with a flare width of 3/4 in.. The 9/16 in. wide rear design of the housing fits into the door rail held in place by a screw that engages the mounting hole in the back end. The adjustment screw is just above the mounting hole.