diver_doug
Contributor
I have a Legend LX and I don't notice much (if any) difference when I'm upside down, but there is a hugh difference when I roll over on my back (so to speak) looking at the roof of a lava tube and such. I really have to draw the air out. Not a big deal once you are aware of it, but the first few times got my attention!!
I think "on his back" was what the OP meant by "upside down".