Listing is for a set of four 4 Service Caster Series #20 1-1/2'' expanding stem swivel casters with 3-1/2'' diameter by 1-1/4'' wide black soft rubber wheels capable of supporting a total weight of 800 lbs. When searching for a reliable and durable solution to your caster needs, look no further than the Service Caster Series 20 expanding stem soft rubber wheel casters.