This medium-duty caster features a double ball swivel raceway type and a grey wheel measuring 1 1/2 x 5 inches. With a load rating of 450 pounds, each swivel caster has a mounting plate measuring 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. The frame is made from zinc with a zinc finish. Use item number WPP6BG for replacement wheels.