Prime-Line Products N 6619 Pocket Door Roller Assembly, 1-1/4 in., Plastic, Convex, Steel Ball Bearings Used as a top roller assembly on pocket door systems; fits E-Z Guide 5/16 in. x 1-1/4 in. outside diameter on 2-1/2 in. x 1-3/8 in. base Convex edge wheel (round edge) Constructed of a plastic wheel with steel ball bearings, assembled to a steel bracket housing