89A Purple Core - Polished concrete and other slippery surfaces for insane grip. Can also be used as a pusher wheel. * 92A Black Core - For use on coated surfaces and tile. Loaded with an insane mix of grip and speed. * 95A Red Core - For use on sticky surfaces, track, or soft skate court where a hard wheel is desired for increased roll. * 98A Green Core - Extra firm for use on coated floors, tracks, and soft skate court * Your Choice of Wheels Sizes - from Low (58mm x 38mm), Mid (62mm x 38mm), and Max (62mm x 42mm) - Bearings sold separately