Made for medium-duty jobs, this durable caster is built to carry loads up to 400 pounds. This caster has a four-inch diameter cast iron wheel with a 1 1/2-inch wide rubber tread encased in a steel frame. The mounting plate measures 3 3/4 inches long and 4 3/8 inches wide with a 5/16-inch bolt diameter. The mounting bolt spacing is 2 3/8 inches long and 3 1/8 inches wide.