The Patagonia Men's Nano Air Vest keeps pace throughout high-output, stop-and-go missions in variabl e conditions. Its exclusive, stretchy and highly breathable fabric package integrates the qualities of fleece, soft shell and puffy by combining a plain-weave liner, warm-when-wet FullRange? insulatio n, and a lightweight-yet-durable, weather-shedding nylon ripstop shell with a DWR (durable water rep ellent) finish, so you can put it on and leave it on. The vest?s soft, supple feel and full mechanic al stretch allow for a close, athletic fit over baselayers and an uninhibited range of motion. The l eft-chest pocket and two handwarmer pockets all close with trim, low-bulk zippers. The center-front zipper has a storm flap and zipper garage, while stretch binding at the armholes and a dual-adjustab le drawcord hem seal in warmth.