AX6868 Progressive Rate Rear Shock Springs (Blue) (2)   This is a set of two Traxxas Progressive Rate Rear Shock Springs, and are intended for use with the Traxxas Slash 4x4. The Slash 4X4’s fully adjustable suspension gives it an edge in any race, and with Traxxas’ progressive-rate tuning springs, you can hone your truck’s handling to an ever greater degree of precision. Custom-wound specifically for Slash 4X4, the new tuning springs are available in four rates to suit any setup. The progressive-rate design allows small-bump compliance without compromising big-hit capability, and the white powder coated finish guarantees lasting good looks. The springs are color-coded to indicate rate, and are sold in pairs in front and rear lengths. Progressive Spring Features: 20% stiffer than stock (Blue) Custom wound for Slash 4X4 Progressive-rate design allows small-bump compliance without compromising big-hit capability Durable powder coated finish Color-coded to easily identify spring rate Spring Rates: Orange: 20% softer than stock Green: 10% softer than stock Blue: 20% stiffer than stock Pink: 10% stiffer than stock  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 Part Compatibility: Traxxas Slash 4x4  Traxxas Stampede 4x4