Hudson Bearings stud mounted machined ball transfer. Solid machined cup with integral 1/4"-20 threaded stem. Hardened and plated for longevity. 5/8-inches main ball rotates on 3/32-inches support balls. Carbon steel housing material. Carbon steel units are sealed and lubricated to ensure maximum life, unless otherwise specified. 33 pounds load capacity. Common applications: air cargo, shears, robotics, military logistics, store fixtures, die handling, laser and plasma cutters, glass and metal manufacturing, medical devices, caster substitution.