Features: Take your PRO636400 MAXX PowerStroke Shocks to the Next Level Tune your Spring Rates and Dial in your Suspension to the Conditions Three Different Upper and Three Different Lower Springs Allow for Nine Different Combinations Overview: This is a Spring Assortment for PRO636400 PowerStroke Shocks. Take your PRO636400 MAXX PowerStroke Shocks to the next level by tuning them to match your specific needs with the optional Dual-Rate Front Spring Assortment pack! Mix and match the different upper and lower spring rates to dial in your suspension to the conditions. The three different upper and lower rates allow for nine different combined spring rate options. Get your pack of optional springs today! PRO636403 | Spring Assortment for MAXX PowerStroke Shocks PRO636400 MAXX is a registered trademark of Traxxas L.P.   : --> Fits: PRO636400 Pro-Line PowerStroke Shocks for MAXX