This medium-duty plate caster has a 1 1/2 x 5-inch wheel with a grey core and a load rating of 450 pounds. Each rigid caster has a double ball raceway swivel sub-type and a zinc frame. 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 WPP5BG for replacement wheels.