Time-honored and field-proven, from starlit starts through benighted finishes, our Nano Puff Pullover remains indispensable. It's both an insulated pullover in late-fall squalls and a micro-belay parka on chilly rock routes. The Nano shuts out wind, sheds snow and traps heat with its warm, low-bulk, compressible and hydrophobic 60-g PrimaLoft Gold Insulation Econow with 55% post-consumer recycled content, and still the most thermally efficient synthetic insulation available, even when wet. The sculpted fit opens up with a deep-venting half-zip that has a soft, wicking interior storm flap and zipper garage. The windproof, 100% recycled polyester ripstop shell glides effortlessly in your layering system, and the pullover packs down to practically nothing and stuffs into a single chest pocket that has a carabiner clip-in loop. Elasticized cuffs and hem seal out wind and trap warmth.