Slipstick CB681 2 Inch Floor Protector Rubber Caster Wheels (Set of 4) 5/16 Inch Stem or Top Plate Mounting Options - Black/Gray Specially formulated polyurethane rubber wheels protect hardwood, laminate, tile, slate, and all other hard floor surfaces Ideal as replacement castors for chairs, tables, racks, file cabinets, machinery and more Includes two options for mounting (5/16" diameter stem with 3/8" grip sleeves) and (1-1/2" x 1-1/2" swivel top plate with 16 screws) Features 38 millimeters (1-1/2 inches) square top plate with screws with 50 millimeters (2 inches) specially formulated rubber wheel Each rubber caster wheel can support up to 66 lbs. (set of 4 holds 264 lbs. maximum)