Traxxas rocker arm set, progressive-2 (90-t)/ spacers (red aluminum) (8) 38-5358 description: progressive-rate 2 rocker arms determine how much the compressive force at the wheel will vary with suspension travel. The higher the rate, the more the suspension will stiffen as the wheel moves upward. Rocker arms are available in 3 progressive rates with 1 having softest rate and 3 being the stiffest. Progressive rate 2 will sharpen handling and reduce brake dive compared to progressive rate 1. Includes red aluminum spacers (8). Replacement part for these models: e-revo vxl brushless revo slayer pro 4x4 summit accessory part for these models: summit