Danny Bell has it right! But you also must place the 120VAC outlet into a wiring receptacle box, something like a short re-model box so that the connections are contained.
The 2" Airstream (and almost every other RV) wall thickness is too shallow for the box/outlet combination. If you limit the positioning to placement in cabinets or counters, you won't have the depth problem.
The back of these dal outlets are larger than most other types and take up almost all of the remodel boxes. I have done many placements, but all were in wood cabinets/night stands with available depth.