Hudson bearings 1 stainless steel main ball with 5/16 stud in a stainless steel housing constructed with corrosion-resistant stainless steel housing for added support and long lasting durability. 1 stainless steel main ball rotates on a bed of 1/8 stainless steel support balls. Solid machined stainless steel cup is hardened. Capacity is 200 lbs . Color finish is stainless . 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.