2 3/16" Bearing UCP211-35 Black Oxide Plated Insert+ Pillow Block Housing Mounted BearingUCP211 35 Black Oxide Plated Insert + Pillow Block Bearing Set Screw Type High Center Height 2 3 16" Inch Inner Diameter UCP211 35 Black Oxide Plated Insert Pillow Block Bearing, UCP211 35 is Set Screw Type High Center Height, Inner Diameter is 2 3 16" Inch. 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 35 Black Oxide Plated Insert