This kit is for the person that wants their existing truck air bag pressure to be automatically regulated. Once installed it requires no calibration, no checking air pressures, it doesn’t use remote controls, or anything electronic, other than your existing on-board air system. This system uses the same quality parts and technology that have been used in the heavy-duty truck industry for decades. Once installed you will never have to think about adjusting your air bag pressure again. Leveling Valves are mounted to the frame on both sides of the vehicle, with linkage that is attached to the axle. As a load is applied and the truck suspension compresses, it moves the arm on the leveling valve, which commands air pressure to be added to the corresponding air bag. As the load decreases and the suspension raises, the leveling valve releases air pressure until the truck is level. There is a delay of a few seconds before the valve will work, this prevents the suspension from constantly moving up and down with bumps in the road while driving. There are multiple mounting options for trucks with different suspension heights and configurations. Included in this kit. Leveling Valves for both sides. Designed and Assembled in the U. A using quality Haldex Leveling Valves. This kit provides the necessary parts to add the ability to regulate your existing airbags automatically, keeping your truck level as your load weight changes. The valves have a delay, so as your suspension moves while driving, the valves will not be constantly adjusting. This kit is compatible with all different brands of rear airbags that are designed for your vehicle model. Air Bags and On-Board Air are required prior to the installation of this kit. Air Bags and On-board air system are NOT included.