Listing is for a set of four (4) service caster series #30 casters, two (2) swivel casters with bolt on swivel locks and two (2) swivel casters with side lock brakes, with 5" diameter by 2" wide polyurethane on cast iron wheel and maintenance free precision ball wheel bearings capable of supporting a total weight of 4000 lbs. (1000 lbs./caster).