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 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