The wind shirt is a relatively new piece of gear coming into popularity these days for good reason. Jackets like Mountain Hardwear’s Kor AirShell do just about everything in the summertime—mine never leaves my backpack (unless I’m wearing it) and ends up on me at least once just about every fair weather day. It might just be the most versatile jacket you’ll own. Here’s why.

Credit: Lauren Danilek

1. Take it Anywhere

When we say these jackets pack up small, we mean it. Like, a pack of golf balls small. Pocket Rocket small. Small enough that you don’t really have an excuse not to carry one. Even on days when I need to carry a full-on rain shell, it can’t hurt to toss my Kor AirShell in my pack for the moments when it’s not really raining, but I still need a little something. The men’s hoody weighs only about 5 ounces and stuffs into whatever microscopic crevice you can find in your pack, so you’ll never know it’s there…until a little bit of wind encourages you to pull it out.

2. It’s The Perfect Fair-Weather Jacket

Why would you need a jacket when the weather is nice? Because, in reality, you do. Even if the sun is shining, hitting the trail early in the morning or breaking above treeline to a light breeze can make you wish you had just a little something extra. Wind shirts like these are the perfect amount of “a little something extra.” The Mountain Hardwear in particular is a single uninsulated later of 20-denier Pertex Quantum Air, which blocks the wind without compromising hardly any breathability. Adding just that little bit of warmth and protection from even the slightest breezes.

3. They’re Surprisingly Waterproof

Granted, wind shirts aren’t designed for real rain. But on days when little to no rain is predicted, you can feel confident taking only a jacket like the Kor AirShell. That’s because the DWR coating that the jacket does have is enough to ward off brief showers, sprinkles, or fog. The last day of our Green Mountain Gravel Growler bikepacking trip saw morning showers that eventually transitioned to a full-on downpour but we started the chilly morning in our Kor AirShells and we all left them on through the light rain until it really started getting heavy. If rain isn’t predicted, you can be fairly sure that the day isn’t going to be a wash-out, and odds are good that a wind shirt can handle the little bit of precip you might get.

Credit: Lauren Danilek

4. Never Take it Off

Unlike most of the other jackets you own, you can feel comfortably moving, even strenuously, in a lightweight jacket like this, giving you very little reason to ever take it off. The material is thin, has no real insulation, and allows moisture to pass through easily, so whether you’re climbing uphill, biking gravel roads, or trail running along the top of the Presidential Range, you can feel comfortable just leaving it where it is.

5. It’s Oh-So Comfy

On top of that, jackets like the Kor AirShell are just a pleasure to wear. Whether you’re wearing it over a t-shirt or an insulating layer like a fleece, it’s soft and smooth against your skin or other layers, there are two zippered hand pockets, and a snugly-fitting hood. Raglan sleeves with underarm gussets allow for a full range of option, whether you’re pulling the next climbing move or reaching for your bike’s drop bars, and elastic bindings on the cuffs and hem keep the jacket from riding up or moving anywhere it shouldn’t.