
Exped
MegaMat Series
Car camping comfort champ, but some side sleepers find it thin.

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Was it the wide version of the Xlite? I have an old, since-discontinued Xlite Max SV which is similar to the Xlite XNT Regular Wide - it seems to be both thicker and wider than the Xlite of old. Normal mummy sleeping pads are no good for me but wide ones are much much better for things like arms going numb!
I'd recommend a thermarest xtherm and a 0 degree quilt for what you are looking for. A sleeping pad with a very high R value like the xtherm means you can get away with a little less sleeping bag/quilt and still be very comfortable all while being quite light amd packable You'll also have some decent insurance if you get an unusually cold night if you sleep in am extra layer. You could alternativley do a thermarest neoair on top of a accordian style mat for a similar R value and extra insurance if the air mattress fails For quilts you cant go wrong with enlightened equipmemt. I have a 900 fill goose down 0 degree quilt and it is extremely packable Do yourself a favour if you go down the thermarest air mattress get the wide 25inch version of each the small bit of extra weight is so worth it compared to the difference in comfort the extra wodth makes
I love my Thermarest neo topo air xl, but have recently picked up a KilosGear Aerocloud elite and it might be my new backpacking mat. More comfortable for side sleeping than even my thermarest.
A NeoAir Xlite is fine at 20F. Cut to 3/4 length, it comes to 9.6 oz and packs pretty small.
They can be cut down to torso length, but from personal experience, let me warn you about that. Torso length doesn’t work great for thick pads like an XLite unless you can find some support for under the knees. Your legs will hyper-extend due to gravity, which is uncomfortable and not physiologically healthy. Adequate head elevation is difficult if not impossible with a torso cut inflatable . I cut mine to 3/4 length such that the knees and head can rest on the pad. That works much better. My cut-down Xlite weighs 9.6 oz. Torso-length CCF pads are actually more comfortable than a torso-length inflatable for the reasons given. They also solve the problem of arms falling off narrow pad and are also lighter and much more durable.
Therm-a-Rest NeoAir XLite with an r-value of 4.5 weighs 370g. You don’t need a stuff sack.
Is there much difference? Both seem about 500g plus change unless I missed something. I’d second getting the right length, I tried a shorter mat years ago and my feet were very unhappy about it
I’ve slept on a regular (non women’s) Xlite on relatively warm ground but at temps in the upper teens for two nights. Had a 20 degree quilt and a puffy on. Didn’t really feel like I was cold on my back side or anything. I’d think I could certainly do it again and be warmer on the women’s version. Also I think gender matters here, I am a dude and I think there’s science that says men sleep warmer than women so ymmv if you are the fairer sex.

Exped
MegaMat Series
Car camping comfort champ, but some side sleepers find it thin.

Exped
Ultra Series
Lightweight side-sleeper comfort, but a bit pricey and bulky.

NEMO
Tensor Series
Ultralight side-sleeper comfort, but slippery and prone to leaks.

Big Agnes
Rapide SL Insulated Sleeping Pad
Comfortable with side rails, but heavy and warmth claims disputed.

Therm-a-Rest
NeoLoft™ Sleeping Pad
Very comfortable, good service, but heavy and bulky for backpacking.

Ranked #1
Exped - MegaMat Series

Ranked #1
Exped - MegaMat Series

Ranked #1
Exped - MegaMat Series

Ranked #1
Exped - MegaMat Series

Ranked #1
Therm-a-Rest - NeoAir Xtherm Series