Powerslides' Infinity wheel is a high-performance training and fitness skating wheel. The Infinity wheels use Powerslides' Race Performance (RP) PU for fast rolling and long-lasting performance. A hardness of 85A is the perfect mixture of grip and roll. This wheel comes in 110mm and 85A. Material: The wheel is made out of SHR polyurethane material. Shape/radius: The size of the wheel is 110mm with a hardness of 85A. Core: The wheel has a 6-star strengthened fiberglas nylon core. Sold in pack of 6.