The Devil wheels are designed for high-level roller skating, and to adapt your skating to many different surfaces, particularly very slippery ones, without compromising on speed and roll. * Given their characteristics, these wheels have been equipped with a rigid bushing that allows them to roll extremely well, with incurring the typical flattening that is expected with very soft traditional wheels, or the slowdowns of polyurethane wheels * The tread is produced by injection of a mix of thermoplastic polymer materials * The rounded finish allows for use with little to no adjustment time *It is possible to combine these wheels with the Professional wheels for a perfect balance between grip and smoothness * Available in seven hardnesses (colors) and two diameters: 57mm and 55mm * Available in sets of 8 wheels (it is at the discretion of each individual reseller to sell units in lower quantities)