55mm Bearing UCP211 Black Oxide Plated Insert+ Pillow Block Cast Housing Mounted BearingUCP211 Black Oxide Plated Insert Pillow Block Bearing Set Screw Type High Center Height 55mm Inner Diameter UCP211 Black Oxide Plated Insert Pillow Block Bearing, UCP211 is Set Screw Type High Center Height, Inner Diameter is 55mm. Black oxide has certain properties and characteristics that makes it ideal for certain applications. It is used to add corrosion resistance and for appearance. UCP211 Black Oxide Plated Insert Bearing + Pillow Block housing