Shepherd threaded stem soft tread caster – 50mm diameter 5/16-18 x 1 stem black this caster is ideal for use with electronic equipment, medical equipment, audio/visual equipment and furniture. Soft 70-75/a durometer tread is made of high-tech thermoplastic elastomer. Offers high load ratings with quiet mobility. Rivet axle provides positive wheel retention. Features 75 lb. Capacity. Wheel diameter measures 50 millimeters. Height of caster is 2-1/4 inches. Black finish.