The state of the art in insulated air mattresses has come a long way since they were first introduced. I recommend them as lighter, more comfortable and warmer-for-the-weight than self-inflating foam filled mattresses. Good insulated air mattresses in regular length (72") mummy shape are around 15 - 17 oz. Most are filled with Primaloft Silver. My new REI FLASH Insulated mummy shaped mattress is 15 oz. and has an R 3.7 value which, coming from REI, means it is a reliable number. This R value puts me comfortably into the teens F. BUT... to keep moisture and bacteria out of the mattresses you need a pump. REI has a nice little foam-filled hand pump, which I bought with my mattress. But now I'm going to exchange it for the alternative, a dry bag pump. So I ordered a Sea to Summit bag pump B/C luckily its nozzle fits my REI inflation valve. Why a dry bag pump? Well mainly to save weight B/C I can use it as a dry bag for clothing. REI also makes a "winter" version of this mattress with 4.4 more ounces of Primaloft Silver insulation and it has a R 5.2 warmth rating, good enough for sub zero temps. So for another measly 4.4 ounces you get a winter air mattress. If you don't mind the noise of a Thermarest Neo-Air X-Therm that sounds like sleeping on a bag of potato chips you get an even lighter, warmer winter mattress for R 5.7. Sea to Summit and NEMO also make very good, light and warm insulated air mattresses. Now I must post a warning (sorry Len, I know you're a BA fan). Most reports about Big Agnes insulated mattresses have owners griping that they are NOT warm enough. Why this is I dunno. FINALLY, if you find your mattress is still too cold you can put leaves, dry pine needles or fresh cut evergreen boughs under your tent floor and/or lay trousers and other non-sleeping clothing under your mattress. Works for me every time when I gamble and lose thinking I can get away with my summer TR Prolite R 2.2 self-inflating mattress. But now with my new Flash Insulated R 3.7 mattress weighing an ounce less than the colder Prolite I'll be taking it for shoulder seasons. ->Yeah, I know, fresh cut evergreen boughs and LNT (Leave No Trace) don't mix but if that's the worst LNT sin I do I think the Great Spirit and the red gods of the hunt will forgive me. Eric B.