This is a set of two AKA Racing 1/8 Truggy Grooved Foam Inserts. Based on the original industry standard closed cell foam insert, the new grooved insert is designed to take advantage of the radial ribs inside the carcass of the Wishbone and Enduro tires while still providing great performance in the Cityblock, I-Beam, Gridiron and Crossbrace tires.