Hudson Bearings two-hole low profile flange mounted ball transfer. Designed to be recessed into the surface of the application in a 1-3/4-inches hole. 1-inches main ball rotates on eighty 1/8-inches support balls. 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. Ball material: carbon steel. Housing material: carbon steel.