Air Lift AirCell REAR Fixed Load Support System: The AirCell Fixed Load Support System by Air Lift is a low cost and maintenance free microcellular urethane spring kit that is designed to reduce vehicle squat and enhance ride comfort. The closed-cell urethane foam that the springs are constructed of provides a cushion of air that protects vehicles with heavy loads from rough bumps and squat. Air Cell Kits are more durable than rubber suspension load support kits and also provide a more comfortable ride by eliminating the harsh jarring sometimes experienced with rubber bumpers when driving on rough roads. AirCell Kits are both economically priced and completely maintenance free. AirCell Kits come with a lifetime guarantee. The part number for this REAR AirCell Kit is 52213 and it fits 2001-2010 Chevy C-3500HD Commercial Chassis models.