Sonic Swiss Bearings are precision honed for maximum speed with Swiss engineered races and balls. Deep groove raceways and premium SUJ2 chrome steel work to withstand aggressive turns and stops. They use a labyrinth seal that defends against dirt and debris, with a nylon retainer to make them light and quiet. Fully serviceable and pre-lubricated with Sonic Super Gel. Contains 16 Bearings. Packaing Doubles as a parts organizer!