Hudson bearings 5/8 nylon main ball with 1/4 stud in a carbon steel housing constructed of nylon steel with a corrosion-resistant plated carbon steel housing for added support and long lasting durability. 5/8 nylon main ball rotates on a bed of 3/32 carbon steel support balls. Solid machined cup is hardened and zinc plated. Capacity is 125 lbs . Color finish is zinc . Hudson bearings is an innovative domestic manufacturer of ball transfers. this stud mounted unit features a hardened and zinc plated machined mounting cup and a stamped metal cap. housing options include stainless steel. main and support ball options include stainless, nylon, phenolic, and delrin. stud mounted transfers can be used in either ball up or down position.