The fabric is constructed from polypropylene Dryarn® and polyamide, providing a protective insulating barrier designed to keep you warm in the winter and cool in the summer. These materials are also super light, highly breathable, and quick-drying to minimise sweating and keep you from getting too warm. On wet days, pair your T-shirt with a waterproof shell, and you'll be protected from rain while staying warm and ready to move. Head out on a trail run or hike knowing the Seamless Ultra-L 2 T-shirt Pack for women will keep you at the perfect temp.