Designed for indoor speed with the legendary Voo-Doo Thane urethane material. 62mm diameter, 44mm core, 9mm tire with a speed lip for maximum control and grip. Nylon composite core is lightweight yet strong. Blue 93A hardness, orange 95A hardness, green 97A hardness. Should be broken in before competition use, Piper suggests to break them in organically for best results. Sold in packs of eight, enough for one pair of skates. Piper returns to their legendary indoor race formula that topped the podium from 1991 until inline took over the race scene. Crack your pack and smell that smell we are all so familiar with. ION rivals Piper's Legend wheels. With a hard core in back, combined with hollow tech in front, ION delivers an ultralight weight with ultra-performance option that competes with aluminum cores.