Based on color X-lite (yellow) - but mine is squared off, not mummy shaped, so I'm not sure just looking at the pics from memory. Looking at camp-mor http://www.campmor.com/outdoor/gear/Product___40750

It has a 2.5 r-value. So yeah pretty low (I don't use this in the winter - I have a Wiggy's mat + my 1980's therm-a-rests.) It might be that I went with the lightest mat I could find, but it isn't the right one for me <sigh> - which is what I ran into with the backpacks (but at least I didn't buy the backpacks )