This is a pack of two "Black - 0.767 Rate" Traxxas Progressive Rate Long GTR Shock Springs. These are the medium rate progressive springs available for the Long shock (TRA7461X). Traxxas offers a wide variety of spring rates for the GTR shocks to provide almost limitless tuning possibilities. The springs are made from high-quality spring steel with durable powder-coated finishes, and the spring rate is indicated by colored dots on the end of the spring. Long Spring Rates: Softest TRA7440: Orange - 0.623 Rate TRA7441: Green - 0.653 Rate TRA7444: Black - 0.767 Rate TRA7445: Pink - 0.810 Rate TRA7448: Blue - 0.892 Rate Stiffest Effects of Shock Spring Changes Shock Spring Characteristic Softer Increased Chassis Roll Increased Traction Better in Bumpy Conditions More Likely to Bottom Out Stiffer Decreased Chassis Roll Decreased Traction Increased Responsiveness