N6531 Features: -Door roller. -Material: Nylon. -Tandem wheels, top mounting, adjustable bracket, round edge nylon wheel, fits 0.75" to 1.75" thick doors. -For doors weighing up to 75 pounds. -Used on Acme and Stanley door systems. Specifications: -Mount: Top. -Diameter: 0.88". -Edge type: Convex. -Dimensions: 7.44" H x 3.81" W x 1.13" D.