Spitfire Formula Four 93A Soft Sliders. Controllable smooth slide and reliable grip. Soft duro with high rebound compound absorbs more impact and vibrations. Unmatched F4 flatspot resistance. Holds speed over any surface.Radials Shape: A round edge, medium width riding surface shaped. Offers the versatility of the classic shape and the width of a conical.Measures 54mm in diameter with a 34mm width and 20.5mm riding surface.