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. Internal Diameter: 35 mm/1.385". Lower un-sprung weight of the SLS coil spring improves performance compared to the FOX standard coil spring. Item Specifications: Stroke (ins): 2.4, Material: Steel, I.D. (mm): 35.200000000000003, Spring Weight: 550,