608ZZ Shielded Grease Ball Bearings 8mm x 22mm x 7mm 608ZZ Shielded Ball Bearings, Bearings are made of Carbon Steel, 608Zz bearings are closed with metal shields to protect the bearing from dust or any possible contamination,608ZZ Bearings are self lubricated bearings (bearings are already greased), 608ZZ is one of the most common widely used bearing, we always suggest mechanical engineers to use 608ZZ in their designs, 608ZZ is economic and standard.