Hudson Bearings stud mounted ball transfer. 1-inch main ball rotates on (80) 1/8-inches support balls. Carbon steel housing material. Main ball is made of carbon steel. Ball support cup is hardened and plated. Protective cover assures low torque and longevity. Carbon steel units are sealed and lubricated to ensure maximum life, unless otherwise specified. 75 pounds load capacity. Threaded stem size: 5/16-18. Common applications: air cargo, shears, robotics, military logistics, store fixtures, die handling, laser and plasma cutters, glass and metal manufacturing, medical devices, caster substitution.