Easiest rolling heavy duty 375 lb. capacity 4 inch swivel and brake caster with standard size 2-3/8"x3-5/8" slotted plate! includes ball bearing construction, non-marking sold thermoplastic rubber tires and 1-1/8 inch wide tread with an overall caster height of 5 inches. They are the perfect replacement caster for any standard wood dolly and also the Snap-Loc dolly. Caster wheels are assembled in the USA.