Mountain Hardwear Kor Airshell Hooded Jacket – Men's Ultralight Pertex Quantum Air Wind Shell

Pertex Quantum Air breathes way better than my old windbreaker while still cutting ridge wind completely. Packs into its own chest pocket to the size of a pear. At $69 this is unreal value.

Weightless, packs tiny, blocks wind beautifully. The hood is a little floppy without a helmet under it, but a cinch adjustment solves most of it.

Featherweight wind armor. Five stars.

As a wind layer it's excellent. I got caught in a real downpour and it wetted out fast, which to be fair is expected — just don't confuse this with a rain shell.

Took this up Rainier's Disappointment Cleaver route and it handled 40mph winds at high camp without a whisper of getting through. The Quantum Air fabric genuinely dumps heat when I'm moving hard. Chest pocket doubles as a stuff sack, which I love. This replaced a jacket costing twice as much.

The main zipper sticks and snags near the top on mine, which is frustrating on a jacket at this level. Wind protection and weight are great, but I shouldn't be fighting a zipper.

Every trail run, every bike ride, every crag day — this thing is in the bag. It weighs less than my water bottle and blocks wind better than jackets three times as heavy. Fit is athletic without being restrictive over a light midlayer. Highly recommend.

Bought it for shoulder-season summit pushes and it's become my most-used jacket. Fabric feels more durable than the weight suggests. Wish the cuffs had a tad more adjustment.

I've owned jackets from the big brands and this beats them all for moving fast in exposed terrain. The stretch fabric doesn't billow or snap in gusts, and it still breathes on climbs. Packed size is smaller than my fist. Truly excellent engineering.

Solid jacket and impressively light, but order a size up if you plan to layer it. The large I got fits me snugly over just a base layer.