Because tire liners must overlap due to variance of the actual interior diameters of a given size of tire, there has always been an edge that is exposed to the tube. Over time, this edge sometimes wears a hole into the tube and actually causes exactly the problem tire liners were made to prevent! We've solved this problem with our new Soft-Tips™. Instead of the potentially sharp, cut edge of hard polyurethane facing your tube, RhinoDillos™ with Soft-Tips™ now show a soft side - literally! Problem resolved.