Integy 20lb spring for Traxxas Revo is constructed of steel , metallic red in color Direct replacement for the Integy MSR Piggy Back Shocks or would be a stiffer replacement for stock Traxxas shocks INCLUDES: Two Red shock springs SPECS: Length: 2.83" (72mm) Diameter: .59" (15mm) Wire thickness: .050" (1.25mm)