Prime-Line B 548 Center Grooved Roller Assembly, 1 in Dia Roller, 5/16 in W Roller, Steel Roller, Concave Roller

This is a roller is used on bottom mount installations. It is a 1 in steel ball bearing roller with a 1/4 in axle hole. The 1/4-20 x 3/4 in carriage bolt inserts through the screen door frame and through the roller and is then secured in the bottom rail with a nut.