A top-of-the-line mountaineering and backcountry skiing jacket the Arc'teryx Men's Alpha SV weighs just over a pound. The use of expedition-tough Gore-Tex® Pro Shell fabric WaterTight zippers and laminated construction techniques all play a huge role in making the Alpha SV such a lightweight jacket despite its full-featured status. This new line of Gore-Tex® is stronger and more breathable than ever before. Micro seam allowances and tiny Gore® seam tape reduce bulk and weight while also making this first-rate jacket surprisingly supple. WaterTight zippers eliminate the need for bulky heavy flaps and the laminated construction pulls it all together without the need for fabric weakening stitches and the additional fabric needed to sew one section of fabric to another. Whether belaying from an awkward stance or skinning across a crevasse minefield the removable HemLock keeps the jacket from creeping out from under your climbing harness. At the same time no-lift gusseted underarms and articulated elbows help the Arc'teryx Alpha SV Jacket remain comfortably positioned so you can focus on the task at hand.