2-1/4" Metal Ball Caster with Rubber Tread, Bright Brass, with 1-1/2" x 1-1/2" Top Plate Capacity: 75 lbs Diameter: 2-1/4" Mounting: Top Plate - 1-1/2" wide x 1-1/2" long Finish: Bright Brass with Rubber Wheel Tread Bearing: Self Lubricating Acetyl Resin Bearing