The Patagonia Nano-Air Shirt Jacket pulls the familiar silhouette of a classic shirt jacket into a realm of genuine warmth and stretch performance, so it transitions naturally from a walk through the neighborhood to a longer outing on a trail without missing a step. The air-permeable Nano-Air stretch ripstop breathes actively as the pace picks up, while the FullRange recycled insulation holds steady warmth when things slow back down. What Our Gearhead(R) Experts Are Saying:"I wore the Nano-Air Shirt Jacket on a late fall trip where temperatures swung wildly between mornings and afternoons, and it handled every condition without any fuss. The snap placket made it easy to vent on warmer stretches, and it looked put together enough to wear straight into town at the end of the day."