SLS coil springs are a lighter weight steel spring with a lower un-sprung weight to improve performance compared to the standard FOX coil spring. They are also lighter than titanium springs at more affordable prices. The 35 mm/1.385" Internal diameter also fits DVO, MRP and X-Fusion shocks.Spring markings: 375 lbs x 2.9"Internal Diameter: 35 mm/1.385"Lower un-sprung weight of the SLS coil spring improves performance compared to the FOX standard coil springItem SpecificationsMaterialSteelSpring Weight375Stroke (ins)2.9 FOX SLS Rear Shock Coil Spring Rear Shock Spring UPC: 611056173527