20mm Bearing UCP204 Black Oxide Plated Insert Bearing + Pillow blockUCP204 Black Oxide Plated Insert Bearing + Pillow block Set Screw Type High Center Height 20mm Inner Diameter UCP204 Black Oxide Plated Insert Bearing + Pillow block, UCP204 is Set Screw Type High Center Height, Inner Diameter is 20mm. Black oxide has certain properties and characteristics that makes it ideal for certain applications. It is used to add corrosion resistance and for appearance. UCP204 Black Oxide Plated Insert Bearing + Pillow block