Carry loads as heavy as 420 pounds with this double ball swivel caster. This medium-duty caster has a 1 1/4-inch wide and four-inch diameter Poly-Loc wheel and a zinc frame The mounting plate measures 4 1/8 inches long and 3 3/8 inches wide with a mounting bolt diameter of 5/16 inches. The bolt hole spacing is 2 3/8 inches long and 3 1/8 inches wide.