Set of 16 Inline Skate Black Ball Bearings with Ceramic Balls Inline Skate ceramic black bearings set. The set has 16 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.