UCFA201-8 Black Oxide Plated Insert Flange Cartridge Bearing Unit 1/2" Bore Mounted BearingUCFA201 8 Black Oxide Plated Insert Flange Cartridge Unit 1 2" Inner Diameter UCFA201 8 Black Oxide Plated Insert Flange Cartridge Unit, the inner Diameter is 1 2" 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 UCFA201 8 Black Oxide Plated Insert Bearing + Flange housingi Flange Cartridge Unit Basic Load (Cr): 12. 8 KN Basic Load