Set of 8 Skateboard Black Ball Bearings with Ceramic Balls Skateboard ceramic black bearings set. The set has 8 Bearings 608 Steel ball bearings with high speed solid Ceramic Balls (not painted or filled with Ceramic Material), bearings have high speed ball retainer, inside them there are Zirconia fibers 7 Ceramic balls, with one non-contact white rubber seal, inner and outer races are made of Steel, 7 balls are made of Ceramic, bearings have one non-contact rubber seal to protect the bearing from dust or any possible contamination.