Set of 8 Skateboard Sealed Ball Bearings 8mm x 22mm x 7mm Set of 8 Skateboard Sealed Ball Bearings, These bearings have built-in rubber seals in order to protect the moving elements from dust or any possible contamination, these are self lubricated bearings (bearings are already greased), the color of cage could be different, grease is low viscosity to ensure fastest possible speeds.