What Our Gearhead® Experts Are Saying: "The Aenergy Light ML is the midlayer I grab for everything—it's warm enough to wear under a shell on ski tours, but breathable and light enough to rock solo on trail runs or shoulder-season hikes. The helmet-compatible hood and zip pocket are dialed for fast-moving missions." When the mission calls for efficiency, we bring the Mammut Aenergy Light ML Hooded Jacket. Whether we're skinning uphill before sunrise or logging high-mileage trails under the summer sun, this ultra-light midlayer adapts to our pace and the season. It delivers just the right amount of warmth while staying breathable through big efforts, and it works equally well as a standalone piece or under a shell. Crafted from recycled polyester, it offers quick-drying performance with a soft, flexible feel. The flatlock seams reduce chafing under harness or pack straps, while the fitted hood slides effortlessly under a helmet. A bonded zippered chest pocket secures the essentials without bulk. From alpine climbs to cool-weather runs, this is a layer we trust when every ounce—and every move—counts.