£165 (regular size) www.thermarest.com
The Xtherm quickly became the de rigeur mat for all season backpacking when it first landed, and with an R-value of 5.7 it’s easy to understand its popularity. It’s a very thick and warm mat, and when fully inflated you don’t touch the ground even when sitting – as you’d expect it consequently takes a lot of puff to blow up! The baffles run from side to side, and it saves weight by having rounded corners, rather than being oblong. Both these things mean it wasn’t the most comfortable in this test, with a tendency to be fattest in the middle and skinnier at the edges. I’d be reluctant to rely on a single inflatable mat on multiday adventures in deep winter, and would always back up with a closed cell foam ‘underlay’, just in case of puncture. However, it was warm, even on its own in overnight temperatures down to -9C. It packs down to a bit larger than a 750ml bottle, has a screw valve and weighs 480g.
VERDICT: Most warmth for weight in this roundup.
BEST FOR: Full on winter camping.
Review by David Lintern @