inline Skate Bearings Nylon Cage 16 Bearings 16 skate bearings, they are Sealed Deep Groove Oil Preserved Radial Ball Bearings with Nylon cage,The Nylon material has a low friction coefficient and less friction means higher speeds. Bearings have Rubber Seals and 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.