This is a set of Shock Springs with various spring tension ratings for the HPI RS4 Pro 4. FEATURES: Steel construction, black, silver, & gold in color (the color of the spring should NOT be confused with the color representing the spring tension rating) INCLUDES: Two Springs Blue Rated 15.3 in/lb Two Springs Silver Rated 16.9 in/lb Two Springs Pink Rated 18.0 in/lb Two Springs Gold Rated 19.0 in/lb Two Springs White Rated 20.3 in/lb Two Springs Yellow Rated 21.7 in/lb Two Springs Red Rated 22.4 in/lb SPECS: Length: 0.98" (25mm) Diameter: 0.67" (17.18mm) OD 0.58" (14.68) ID tjt 120504 ir/jxs