Can't remember the difference between a cylinder and a cone from eighth period geometry? Let us break it down for you: With a conical wheel shape you get a wider riding surface and a slight cutaway design for unmatched control and lasting speed. This coupled with 99a Formula Four Urethane and the Spitfire Formula Four 99a Conical Skateboard Wheels are a slick set of rollers that resist sticky spots while letting you lock in your grinds. What this has to do with math class, we're still not sure.