The Seba Speed Inline Speed Skate Wheels are a terrific choice for those that want a fast and smooth rolling speed wheel. The 85A hardness Speed formula used is an upgrade from the CC speed wheels and does a better job at balancing durability and grip, providing quality rolling on all surfaces types, whether its rough asphalt or smooth concrete. The spoke hubs enable great power transfer and stability while providing flex when needed. Fits standard 608 sized bearings, sold individually.