I did forget this.
A 5000 BTU or 5500 BTU unit will not fit under the seat.
A 3000 BTU unit will.
Isn't this a bit small for the space?
When the top is up on the campmobile I think it maybe too small to work
right.
I measure the hole today.
A Matag 5000 or 5500 is too large to fit in the length of the box and
too tall to close the seat lid.

Good Evening,

Fred