Air compressor for load leveling air bags. Which reminds me, I need to get mine ordered.
Most likely an air ride suspension.
An air lift for the suspension
I take it you work for Camping World?
That’s the air manifold for an airlift load level system. Looks like the compressor is on the other side of the frame. There should be a control panel, or remote somewhere.
Source: I work with an Rv dealership and need to know what this is