On those cold days outdoors it’s important to wear a breathable base layer that keeps you warm and balances temperature. That's why they have developed the Trift line that features a Merino wool/polyamide blend. The wool content insulates and inhibits odors, the synthetic fibers make the longsleeve durable and quick-drying. Seamless construction allows a body zone- specific arrangement of different material structures for optimal regulation of your body temperature. The half-length zipper allows extra ventilation. Mammut obtains its Merino wool from suppliers who care about animal welfare and are against mulesing.