Montane Atomic Outdoor Jacket The Montane Atomic Outdoor Jacket now features PERTEX Shield waterproof fabric technology. Lighter, stronger and more breathable, you'll feel the difference when you're breathing easy half-way through your trek. As well as being hugely protective the jacket is surprisingly flexible. It won't weigh you down at just 325 grams and with articulated arms for improved reach and flexibility, you'll see an improvement in performance as well. The jacket is ideal for any outdoor trekker, whether taking on a mountain ascent, or simply going for a walk in the rain, this jacket is designed to be hugely versatile and give maximum performance, whatever the challenge.