Hudson Bearings Drop-In style ball transfer. Integral flange at top allows unit to be dropped into 1-3/4-inches diameter hole. 1-inches main ball rotates on 1/8-inches support balls. Ball support cup is machined from solid steel and is hardened and plated. Plated steel cover. Carbon steel units are sealed and lubricated to ensure maximum life, unless otherwise specified. 200 pounds load capacity. Ball material: carbon steel. Housing material: carbon steel.