Thermarest Neoair xtherm max I think is it's called the one I have, it's rectangular not tapered. I can't remember all the designation crap it's gray has a really high r value and was the #1 air pad when I was doing ultralight backpacking and it and rocks. I use mine with a Thermarest ultralight cot and got the lady a big agnes Q Core SLX something or other. She seems to really like it and it's slightly thicker than my Neoair with raised edges so she doesn't roll off but it does have a lower r value. As much as I hate setting it up every night and taking it down every morning my favorite piece of sleep gear is the cot of all things even with the pad it's a lifesaver. But I have 2 herniated discs in L4 and L5 and am about to have a fusion so there's that.