Skateboard Bearings Nylon Cage 8 Ball Bearings 8 skateboard bearings, they are Sealed Deep Groove Oil Preserved Radial Ball Bearings with Nylon cage.The Nylon material has a very low friction coefficient and less friction means higher speeds. Bearings have Rubber Seals, Bearings are made of Chrome Steel, each bearing has 2 Rubber Seals to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with Oil.