Take Patagonia's classic original Nano Puff Pullover, add a full-length zipper for greater all-around ease and you have the versatile Nano Puff Jacket. It is windproof and weather-resistant enough to wear as an insulated shell in a sudden squall, trim enough to pull on for chilly rock pitches (and still see your footholds) and warm enough for light belay parka duty on quick alpine dashes. The wind-blocking, moisture-shedding 100% recycled polyester shell also glides effortlessly, whether worn as an outer or midlayer. Low-bulk, hydrophobic, highly compressible PrimaLoft One (60-g) insulation traps heat with remarkable efficiency, even when wet. It packs down to practically nothing and stuffs into an internal zippered chest pocket that has a carabiner clip-in loop. It also has two zippered handwarmer pockets, elasticized cuffs and a dual-adjust drawcord hem to seal out wind and seal in warmth.