Listing is for a set of four (4) Service Caster Series #20 1-3/8" expanding stem 316 stainless steel swivel casters, two (2) with top locking brakes, with 5" diameter by 1-1/4" wide glass filled nylon wheels capable of supporting a total weight of 1,200 lbs. (300 lbs./caster). When searching for a reliable and durable solution to your caster needs, consider Service Caster?s 316 stainless steel glass filled nylon casters. SS316 casters are ideal for light and medium duty material handling, carts, equipment, and shop projects. Built with 316 stainless steel, which contains additional molybdenum and nickel content, making it more corrosion resistant than standard 304 stainless steel. The glass filled nylon wheels provide very low rolling resistance, show a high resistance to many aggressive substances, will not flat spot, and under normal operating conditions are maintenance free. Resistant to most chemical and oils, these glass filled nylon wheels will keep you safely moving forward. Mounting options include top plate, bolt hole, expanding stem and standard and metric threaded stem sizes.