6306ZZ Shielded Ball Bearing 30mm x 72mm x 19mm 6306ZZ Shielded Ball Bearing, material is Chrome steel, 6306ZZ is Electric motor quality, each 6306ZZ bearings is closed with 2 Metal Shields, one Shield from each side, to protect the bearing from dust or any possible contamination, also 6314ZZ bearing is pre-lubricated with grease, Bearings 6314ZZ has industrial packaging.