What Our Gearhead(R) Experts Are Saying:"The Air Zone construction makes this pad work at its weight. The foam is mapped to where my body loses heat, so the pad stays warm at the shoulders and hips without carrying extra material through the middle. It handles three seasons of camping without asking for more pad than the trip needs."The Sea to Summit Camp Self-Inflating Sleeping Pad carries an R-value of 4. 2, which puts it comfortably into three-season territory and handles shoulder-season temperatures that would push a lower-rated pad past its limit. That warmth rating is uncommon for a self-inflating pad at this weight and reflects the Air Zone construction doing real work rather than adding foam weight to hit a number.