These are the optional Black Rate GTR Shock Springs for use on the Traxxas 1/16 E-Revo VXL 4WD RTR. FEATURES: Steel construction Red in color 2.22 rate, black INCLUDES: Two GTR Shock Springs REQUIRES: Installation on the vehicle SPECS: Length: 19.75mm (0.78") Outer Diameter: 13.75mm (0.54") Inner Diameter: 10.95mm (0.43") Wire Diameter: 1.4mm (0.06")