The Bolt Speed wheels with an all new high-performance formula, constructed from a high-speed urethane with a race profile for a light and fast roll. This formula features both high rebound and durability and is the performance choice for X-Trainers looking to outfit their 90mm and 100mm skates. Both the 100mm and 90mm wheels come with ILQ-9 bearings and aluminum spacers. The 90mm are available in 4 and 8-packs and the 100mm in 4 packs. All wheel packs come in cool, reusable storage bags.