Sea to Summit Comfort Plus XT Insulated Air Sleeping Mat

The Sea to Summit Comfort Plus XT Insulated Air Sleeping Mat is the most robust pad in the Comfort line covered here — dual-chamber Air Sprung Cells, an ASTM F3340-18 R-value of 4.7, and 7.6 cm of thickness push it into genuine 4-season, winter-capable territory. Insulation comes from a reflective Exkin Platinum layer plus synthetic Thermolite HL-1, and two independent valves speed up inflating its larger air volume. The Regular Wide size tested here (186×64 cm) is generously long and wide, good for taller sleepers or anyone who likes room to move — the trade-off is a weight of 1185 g and a packed size of 28×14 cm, clearly outside ultralight territory. A warmth-to-weight ratio of 3.97 confirms this pad is built for maximum insulation and space rather than minimal weight. It suits winter trips, cold-season backpacking, or anyone who values sleep quality enough to accept the extra pack weight.