Listing is for a set of four (4) Service Caster Series #20 casters, four (4) swivel bolt hole casters with 3” diameter by 1-1/2” wide semi steel cast iron wheels. Supports a total weight of 1,200lbs (300lbs/per caster). When searching for a reliable and durable solution to your caster needs, consider Service Caster’s Series 20 roller bearing semi-steel cast iron 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, while the semi-steel wheels are abrasion resistant and rugged, maintaining effortless rolling under heavier loads, and provides a cost-effective solution over steel wheels. The roller bearing is capable of carrying greater loads while also providing smoother rolling motion. It has a split outer race shell into which the roller assembly is inserted. Combination seal/thrust retainer washers protect the bearing from dirt, water, and chemicals. They also help absorb thrust friction (Note: roller bearing must be used with hardened spanner bushing or hardened shaft). Mounting options include top plate, bolt hole and standard and metric threaded stem sizes. Service Caster is unsurpassed in quality, reliability, and excellent customer service. Count on us to move you forward.