This listing is for a Set of 4 Casters which includes 2 Swivel Casters and 2 Rigid/Fixed Casters of our CasterHQ Heavy Duty Industrial 4" x 2" stainless steel Casters. This 4 Pack listing is priced competitively at wholesale pricing to provide stainless casters with the fast shipping. Our Stainless Steel Caster is made to withstand harsh environments and applications that would normally rust and corrode standard zinc plated casters. All metal parts are made entirely out of high quality 304 STAINLESS STEEL. Popular applications include; clean rooms, laboratories, medical & hospital facilities, animal cages, pharmaceutical plants, autoclaves, food processing, bakeries, dairy, food service, catering, hospitality, chemical factories, marine environments, fisheries, cruise ships, etc. Stainless Steel Casters are designed to prevent rust that would normally accumulate on standard zinc plated casters. Stainless Steel Casters are made for harsh, wet, corrosive environments and manufactured using the highest quality S304 Stainless Steel to extend the life of the Caster. Our 4 Inch Stainless Steel Caster also come with Stainless Steel Zerk Grease Fittings for easy lubrication points and maintenance. Plate Size is an industry standard 4" x 4-1/2" overall size with a bolt hole pattern of 2-5/8" x 3/5/8" slotted to 3"x3". Our Blue Solid Polyurethane Wheels are a Solid Cast Polyurethane Elastomer with a Durometer / Hardness Shore D 60 (+/-5). This Wheel comes with Stainless Steel 3/4" Roller Bearings with a Stainless 1/2" Spanner and tightened down with a Stainless Steel Zerk Axle and Lock Nut. Temperature range for the wheel is -50 degrees Fahrenheit to 180 degrees Fahrenheit. The design of the Polyurethane Wheel prevents de-lamination that you would normally see on most caster wheels extending the life of our wheels to save you money on frequent replacements. Each Caster can withstand up to 800 lbs weight capacity. The Swivel Raceways include Stainless Grease Fittings.