Mostly spare Air Lift parts from various truck air bag kits I bought over the years, but this is a compressor up under the pin box that feeds the airbag and remote switch and bleed valve out by the pin box light switch. Both the gauge and air chuck are tapped into the compressor line with Air Lift "T". The switch on this one only lights up the gauge, but you could use it to power the compressor if you didn't want to install a remote switch out by the edge of the RV. To be honest, I use the gauge now more than the arrows on the pin box, as it is more accurate. The arrow on the shock changes as soon as you move and you have to jump out and readjust it.
