The Taiss ML Jacket uses Polartec(R) Power Stretch(TM) fleece to wick moisture and regulate temperature at altitude, so the chill doesn't set in once we stop moving at the summit. Higher-placed, harness- and backpack-compatible pockets stay reachable under a pack or a climbing harness, and a flat-seam construction avoids chafing under a loaded strap. The face fabric and lining both run on recycled polyester, cutting down on new material without sacrificing stretch or warmth. What Our Gearhead(R) Experts Are Saying:"I've worn this on a ski tour where the climb had me sweating and the summit had me shivering within minutes, and it handled both without a layer change. The fabric wicks fast enough that I never hit that clammy, overcooled feeling at the top."