Designed, tested, and manufactured in Durango, Colorado, the RUNT by DSD is the original dual chamber air spring cartridge. The patented design provides a near-linear compression curve for a "coil-like" feel while maintaining infinite adjustability. Easy drop-in installation Half the price of a coil conversion Coil-like suppleness and mid-stroke support Built-in tunable progression, or "bottom-out resistance" ½ lb. lighter than coil conversions, and only 20 grams heavier than the same amount of tokens or spacers Maintains your fork's air spring compatibility The RUNT still uses air, so unlike a coil spring, the progressiveness of the curve is infinitely adjustable. For example, more aggressive riders looking for additional bottom-out resistance can add air to the high chamber to create a more progressive curve. Increasing progressiveness with the RUNT doesn't affect small-bump compliance — instead, it adds bottom-out resistance from the end of the mid-stroke through the end of travel. Compatibility: All FOX 36 Models (Factory, Performance, and Rhythm, SL, and E-Optimized) 2018 and newer with NA2 air spring Marzocchi Z1 Bomber