ICONs 2.5 Aluminum Series shocks are designed and built to give your vehicle outstanding performance off - road and a smooth ride on the street. These shocks are configured specifically for each application in both length and damping tune. Featuring one - piece impact extruded aluminum cylinders, these 2.5 Aluminum Series shocks offer lighter weight, improved corrosion resistance, and a more uniform finish than traditional plated steel cylinders. Like all ICON'S Shock Absorbers, 2.5 Aluminum Series shocks are 100 rebuildable and 100 revalveable. For piggyback and specific remote reservoir applications, ICON'S unique use of a 6061 billet aluminum manifold a few inches below thetop cap of the shock creates an internal Bump Zone that when used creates an additional 20 of damping force. This additional force helps prevent harsh bottom outs and controls the suspension when compressing at high velocity. The ICON CDC Valve is an externally adjustable valve that restricts oil flow into the reservoir which creates 10 levels of compression damping force ranges.