Protection up front, breathability in the back. The Patagonia Nano-Air Light Hybrid Jacket was created to put an end to the clam factor that often accompanies hefty aerobic effort in chilly temperatures and keep you at optimum operating temperature. A light layer of warm, stretchy and breathable FullRange insulation (40g) is wrapped in a lightweight yet durable, 100% nylon ripstop shell with DWR finish for just the right amount of wind- and weather protection up front. Everywhere else, a super stretchy, airy waffle knit swiftly wicks moisture, controls odour and dissipates heat. Other details include a sleek centre-front zipper with a zipper garage that's easy on the chin, stretch-knit cuffs with thumb holes to ensure critical coverage, low-profile zippered pockets for comfort under a harness or pack and a stretch binding hem to seal in warmth.