1-1/2 inch concave (grooved) steel rollers. Ball bearing. Stamped steel housing with rear adjust. It has two machine threaded mounting screw holes on the top of the housing and two 1/4-20 threaded mounting holes on the end. Top mounting holes are 1-5/8 inch on center. The housing is 13/16 inch wide with a 1-1/8 inch flare, 1-15/32 inch tall and 4-1/2 inch long. Used by a variety of patio door manufacturers.
