Atomik RC Performance Speed Tuned Pinion Gear Set fits the Traxxas 1/16 Slash 4x4 and Other Traxxas Models, includes 23T, 28T, and 31T Pinions Precision Made and Tuned for Performance. Hardened Steel for Maximum Durability. Atomik RC Offers a Full Line of Hop Ups for your Traxxas Model, Available in Blue, Red, and Gunmetal Also Fits: Traxxas 1/16 Slash 4x4, Traxxas 1/16 E-Revo, Traxxas 1/16 Boss 302 Mustang VXL