The CeramicSpeed Zipp 8 Wheel Kit is based around friction reduction for more speed. This version is compatible with Zipp 77D/177D and 76D/176D NSW Disc, ZR1, and Cognition Disc hubs from 2015 forward. The kit comes with six bearings which match your Zipp hubs. These are the standard bearings which are less expensive than the coated version while maintaining a long lifespan and low friction. Due to the high velocity of bearings as you ride, this lack of friction can have a massive effect on your performance. With the CeramicSpeed Wheel Kit, you can assure that performance is as smooth as possible.