What Our Gearhead(R) Experts Are Saying:"The Flex 3R is the only foam mat I'd trust for alpine bivies. It's surprisingly warm for a closed-cell pad and way more comfortable than I expected. I use it solo for fast-and-light trips or under my inflatable to guard against rocks and cold."When the ground's frozen and the margin for comfort is thin, the Flex 3R Sleeping Pad delivers unmatched durability and warmth in a foldable, closed-cell foam design. This is the thickest and warmest pad in the Flex series, purpose-built for alpine adventures, high-altitude nights, and demanding terrain where failure isn't an option. With 3. 1 inches of thickness and an R-value of 2. 7, it adds reliable insulation against frozen ground and boosts warmth under any inflatable pad. The folding construction deploys instantly, and the Oeko-Tex(R) certified IXPE foam stands up to repeated use in rocky, snow-covered, or abrasive environments. Whether used alone or as a system base layer, this pad's performance punches far above its weight.