This medium-duty rigid plate caster has a load rating of 300 pounds. Each caster features a 1 1/2 x 5-inch wheel with a black core and a zinc frame and finish. The mounting plate measures 4 1/8 x 3 3/8 inches, with a 5/16-inch mounting bolt diameter and an inside/outside bolt hole spacing of 2 3/8 x 3 1/8 inches. Use item number WBZ5BB for replacement wheels.