Fox Racing Shox Evol Shock Upgrade Kit 803-00-198 Complete kit to upgrade FLOAT&reg;, FLOAT&reg; II, and Float&reg; III shocks to FLOAT EVOL&trade; With this kit, you will gain a plush bottomless feel without altering ride height or roll stiffness When combined with the infinite adjustability of the main air spring, the EVOL&trade; air chamber allows the shock's spring curve to be tuned for any conceivable rider weight and/or terrain condition EVOL&trade; air chamber regulates spring rate in the final portion of the stroke and controls the bottom-out characteristics of the shock Adjusting this pressure is similar to changing the spring rate on a coil over shock