Skateboard Bearings NYLON Retainer & Sealed 100 Bearings 608-2RS 100 ball bearings with high speed nylon cage, bearings are closed with seals to ensure the best closures without affecting speed (not like the orinary rubber seals), Bearings have Nylon retainer with a non-contact seal, each bearing has 2 non-contact seal to protect the bearing from dust or any possible contamination, these are self lubricated bearings.