model: Enduro, stroke: 65mm/2.6", rate: 540-610 lbs, color: black, , Adjustable base spring rate by changing the length of effective coils, Includes spring, adjuster, and 5 Delrin performance adapters that allow the spring to spin while compressing and also adapt to a variety of shocks on the market, Coil is made of super high tensile spring steel similar to "lightweight" springs (which is why Sprindex is lighter than regular springs) in order to handle the stress of the system when adjusted to its highest spring rate setting, as well as reduce coil mass, Behaves like a regular coil that has a spring rate the same as your adjusted Sprindex spring rate. Adjusting your Sprindex does not change the length of the coil and so does not change your preload. Preload is adjusted normally and with the threaded ring that came with your shock, The first 80% of the stroke has a linear rate while the last 20% of the stroke has a progressive rate to help smooth bottom out, Model only designates stroke length