Traxxas 8441 139mm GTR progressive shock springs (+2 (1.250) rate, blue stripe) (natural finish). Fits Traxxas Unlimited Desert Racer. Use Traxxas stock and hop-up replacement parts to get the most out of your Traxxas RTR vehicles. This product is made from high quality materials and designed for long-lasting performance. This is replacement hardware for use on Traxxas vehicles; consult your users manual for exact parts listings.