What's with the ridgey exterior walls on the Jayco TTs?

gmwphotos, like I was saying in layman's terms that most people can understand (like myself, as I'm not in the business)

"120 - 130 pounds per square inch. And that's vacuum pressure, not clamping"

I don't know anything about atmospheric measures or atmospheric pressures.

So, did I answer your questions?

Thanks,

WoodGlue