Rush Bearings have the best combo of performance, durability, technology and price on the market. Within each twice-inspected high-grade steel case are bearing balls with a micro finish, shaped to perfection, slicked with our own corrosion preventing nano-tech lube, cradled in a ball retainer made of a special formula of heat resistant, non-corrosive nylon, which greatly reduces heat and friction. Plus, the non-contact, non-friction rubber shields makes cleaning and lubricating your bearings a breeze. Our Stability Locking System, features wide flanged CNC Precision Spacers to hold each bearing perfectly in place, stabilizing your wheels at any speed. Or in other words, these bearings are LONG LASTING, SUPER SMOOTH and SUPER FAST, and did we say super affordable? 'narff said.