6011ZZ Shielded Ball Bearing 55mm x 90mm x 18mm 6011ZZ Shielded Ball Bearing, Material is Chrome steel, 6011ZZ is Electric motor quality, each 6011ZZ bearings is closed with 2 Metal Shields, one Shield from each side, to protect the bearing from dust or any possible contamination, also 6011ZZ bearing is pre-lubricated with grease, Bearings 6011ZZ has industrial packaging.