Many hikers and backpackers go boot shopping with one ambitious goal: to find boots to wear for all of their trail walking. Most eventually realize this isn’t terribly realistic—they wind up either with burly boots that are too hot and heavy for day hiking and light backpacking, or lightweight boots or shoes that lack support for carrying a backpack. In two decades of testing boots, I’ve usually been disappointed in my quest for such a boot as many are simply too hot. That’s why Mammut’s Comfort High GTX® SURROUND® Boot caught my eye. Here’s a light boot—just north of two pounds a pair—with ankle support and GORE-TEX SURROUND® product technology, which I’ve found delivers excellent breathability in other boots I’ve used. I wore them carrying a 10-pound daypack on the 10-mile Around the Mountain trail in Idaho’s Boise National Forest (with some 1,500 feet of elevation a gain and loss) as well as on trails in the Boise Foothills. On the Around the Mountain trail, we started out under partly cloudy skies with temperatures in the low 50s, but it became mostly sunny and temperatures climbed to 70 degrees before we finished the hike. If ever there was a day to test the breathability of such a product in its natural habitat, this warm day was it. Sunlight, strong pace, hills, and a boot with an over-the-ankle cut; I’ve faced this setting before and the result was sweaty discomfort. But that wasn’t the case with these new boots. The GORE-TEX SURROUND® product technology kept my feet dry, thanks to side vents in the boot’s shaft that released moisture and heat, and a spacer layer between the outsole and the inner lining that created airflow under the foot. When I pulled the boots off back at my car, my socks were dry. And dry feet make for one happy hiker. So can the Mammut Comfort High GTX® SURROUND® Boot perform as a boot of all trades, crossing over from day hiking to light backpacking? For starters, anyone who’s backpacked or tackled a multi-day hike knows the likelihood of rain or wet trail crossings. So waterproofing is a must. Thankfully, these boots leveraged GORE-TEX SURROUND® product technology that kept the elements out and allowed sweat to escape all the same. My feet never felt overheated. The boots also utilize an EVA foam midsole with a TPU insert for arch support, making for a light and highly flexible product that enables a very natural stride. This may, however, limit how much weight you can comfortably carry without getting achy feet from the typical pounding of the trail. Seasoned backpackers ought to be more than comfortable, though. The mesh fabric in the uppers improved the boot’s breathability. The boot is also made with ripstop textile and reinforced with liquid rubber overlays—not to mention a beefy toe bumper that enhanced the durability of the boots. And the gripex outsole, with multidirectional lugs and two different rubber densities, was clearly built for rugged terrain. The fit was comfortable with a soft feel, and roomier than some boots. The fit seemed medium-to-high volume as my very average feet slid forward slightly on downhills. Is the Mammut Comfort High GTX® SURROUND® Boot an all-around boot for day hiking and light backpacking? Some backpackers will want more support, but I think people accustomed to lightweight footwear and light loads—such as thru-hikers and ultralighters—will love these boots for trips where they face a greater threat of hot feet than days of endless rain.