Formulated to give you a harder faster ride the 99 Duro Formula Four Wheels from Spitfire feature unmatched flatspot resistance, smooth anti-stick slide, high rebound compound and are shaped to last longer. Tested by the Spitfire team, Formula Four are their best skateboard wheel yet. The 99D Spitfire x Thrasher Oath Radial Full F4 Wheels are 58mm in diameter and have a full running surface with rounded edges for more control, speed and a responsive slide. Unmatched Flatspot Resistance Smooth Anti-Stick Slide High Rebound Compound Radial Shape (Full Running Surface, Rounded Edges) 58mm Diameter Set Of Four 99D