The 70mm Butterball Wheel offers the same formula and shape, but in a more compact package, so you can fit on your double kick. You might find a little better control and responsiveness with this smaller version of the Butterball. *All wheels are sold as a set of 4 SPECS 70mm Diameter 80a Durometer 40mm Contact Patch FEATURES Butterballs Slide Formula Round Lips for Smooth Slides over Cracks and Road Imperfections Stoneground for Immediate Slides Centerset Core