4. The LevelPro system uses a combination of air pressure sensors and ride height sensor arms to accurately monitor the 'bags. The sensors mount to the frame and the upper control arm. As the suspension cycles, it moves the sensor arm and tells the brain box where everything is at. Once you've aired the truck to ride height, you push a button on the controller to set it, kind of like a preset on your radio. From then on, it will only take one button to bring it back to the proper ride height. The control box gives you three of these preset buttons.