What Our Gearhead® Experts Are Saying: "I’ve been layering the Kor Alloy Crew on alpine missions and cold morning hikes. It’s shockingly breathable but still warm when the wind picks up. The AirMesh underarms dump heat fast, and paired with a shell, it becomes a killer midlayer for changing conditions."For high-output missions that demand constant thermal balance, the Mountain Hardwear Kor Alloy Crew is one of our most trusted midlayers. From brisk morning starts to summit scrambles, this piece keeps us moving comfortably through fluctuating temps and activity levels. It breathes when we need it to and insulates when we don't, striking the perfect balance for backpacking, alpine climbs, or fast-paced treks. The technical build combines Pertex Quantum Air stretch ripstop fabric with strategically mapped insulation, blending AirMesh for breathability and PrimaLoft Gold Active for dynamic warmth. Underarm zones ramp up airflow when we’re working hard, and the deep front zip lets us dump excess heat quickly. We love the kangaroo pocket with an internal secure stash, and the sleek cuffs seal in warmth without bulk.