Listing is for four (4) Service Caster Series #20 swivel casters with a 3-1/2? diameter by 1-1/4? wide gray thermoplastic rubber wheels and a 3/4" square stems with top lock brakes. Supports a total weight of 920lbs (230lbs/per caster). When searching for a reliable and durable solution to your caster needs, consider Service Caster?s Series 20 square stem thermoplastic rubber casters. The Service Caster Series 20 is ideal for light and medium duty material handling, carts, equipment, and shop projects. The zinc plated finish provides durability under any condition, and the soft, quiet and non-marking thermoplastic rubber wheels perform especially well on hard surfaces such as concrete, tile, and wood. They are resistant to water, oil, and grease and will keep you safely moving forward. The square stems are designed to be bolted or riveted onto the inside of angled iron legs or against any flat surface. Service Caster is unsurpassed in quality, reliability, and excellent customer service. Count on us to move you forward.