Listing is for a set of four (4) Service Caster Series #30 swivel casters with 4" diameter by 2" wide phenolic wheels capable of supporting a total weight of 3,200 lbs. (800 lbs. per caster). These casters feature an extra large top plate that is 5" x 5-1/2" overall and has a bolt hole spacing of 4-1/8" x 4-1/2". When searching for a reliable and durable solution to your caster needs, rely on Service Caster Series 30 top plate phenolic wheel casters. The Service Caster Series #30 is ideal for medium and heavy duty material handling, carts, equipment, and shop projects. The zinc plated finish provides durability under any condition, and the phenolic resin wheels are highly resistant to impact damage, providing protection for floors in commercial and industrial settings. Not only are they resistant to water, oil, and grease, but because they are non-metallic, these wheels are spark proof, keeping you safely moving forward. Service Caster is unsurpassed in quality, reliability, and excellent customer service. Count on us to move you forward.