Pro-Line Arrma 4S BLX PowerStroke Rear Spring AssortmentThe Pro Line Arrma 4S BLX PowerStroke Front Spring Assortment is a tuning option for Pro Line PRO6359 01 PowerStroke Rear Shocks. Take your PRO6359 01 ARRMA PowerStroke Shocks to the next level by tuning them to match your specific needs with the optional Dual Rate Rear Spring Assortment pack. Mix and match the different upper and lower spring rates to dial in your suspension to the conditions. The 3 different upper and lower rates allow for 9