Plain Back tandem plain back roller assembly with two 1-1/4 inch concave or grooved steel ball bearing rollers. The stamped steel housing is adjustable. Used by Keller as well as other manufacturers primarily on vinyl patio doors. The housing is 11/16 inches wide, 1 inch tall and 3-1/8 inches long with a 1/4-20 threaded mounting hole on the back end.
