TOP ROLLER DERBY WHEEL USED BY CHAMPIONS The Bont Evolve roller derby wheel has extremely high roll, rebound, grip and wear properties. Made from ultra high grade urethane The hub is made of lightweight polycarbonate and was designed with the aid of CAD to provide a super rigid structure for high speed cornering There is a size and hardness to suit your needs. Perfect for any indoor surface Dimension are 59x38mm. Hardness Blue 88A, Purple 92A, Red 95A, Black 98A Bring your skating up a notch with the next evolution in skate wheels. The Evolve wheel has extremely high roll, rebound, grip and wear properties. This is achieved through the use of ultra high-grade urethane. The hub is made of lightweight polycarbonate and was designed with the aid of CAD to provide a rigid structure for high-speed cornering. Size: 59x38mm Color and Hardness: Blue 88A, Purple 92A, Red 95A, Black 98A