Spitfire Formula 4 features more speed and control on all surfaces, unmatched flatspot resistance, smooth anti-stick slide, high rebound. 100% true performance urethane. The Conical Full is a wider version of the Conical Shape. Wide riding surface, cut in sidewalls to decrease weight. A solid, controllable shape for all terrains. 56mm, 101A. Sold in a set of 4.