For the ultimate in bump and jump control, Traxxas Big Bore shocks are the perfect addition to your Traxxas model. Hard-anodized aluminum bodies, PTFE-coated shock bores, and titanium nitride coated shafts offer incredible durability and near frictionless operation for ultra smooth damping and long-lasting performance. Progressive rate springs for 2WD Slash are included; for best performance with Rustler, Bandit, Stampede, Craniac and Skully install the springs included with your model.