6700ZZ Ceramic Shielded Ball Bearings Lot of 10 Bearings 6700ZZ Ceramic Shielded Ball Bearings, Bearings are made of Chrome Steel, each bearing has 2 metal shields to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with grease, Ceramic Balls are the highest standard of balls that can make your bearings live at least 5 times more than any other bearings.