Listing is for a set of four (4) Service Caster Series #KP30 casters, two (2) swivel and two (2) rigid casters, with 4" diameter by 2" wide rubber on cast iron wheels capable of supporting a total weight of 1,600 lbs. (400 lbs./caster). When searching for a reliable and durable solution to your caster needs, consider Service Caster Series KP30 moldon rubber on cast iron wheel casters. The Service Caster Series KP30 is ideal for material handling, carts, equipment, and shop projects. The moldon rubber tread performs especially well on hard surfaces such as concrete, tile, and wood, while the cast iron core wheel stands up to heavier loads with a stable and secure roll. Featuring a Kingpinless hot forged ASTM1045 steel design that increases caster durability and integrity, the series KP30 eliminates problems associated with kingpin failure due to severe shock loading. In addition, the Kingpinless design features 3/8” diameter HRC45 steel ball bearings which absorb thrust and load in severe environments. Lastly, Service Caster’s Series KP30 casters are finely crafted with grease fittings, and 4 position notches to accept 4-position locks. These highly versatile casters are ideal for a wide range of applications, such as dollies, platform trucks, warehouse carts and freight terminals. Even drywall carts, welding carts, and wall panel carts will be ready to roll on the Series KP30, keeping you moving forward.