This set of rebuild parts for Traxxas Ultra Shocks includes upper and lower spring retainers and both two and three-hole pistons. Adjust your Ultra Shock's compression and rebound by using the two or three-hole pistons. 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 user's manual for exact parts listings.