When you hear "wool" you might think of heavy winter sweaters and socks, but wool isn't just for chilly nights and long days on the ski hill. With the Bjorn Daehlie Summer Training Short-Sleeve Wool Shirt you can harness the temperature-regulating performance of merino wool even when you're running and training in warm summer weather. Thanks to its natural breathability and wicking properties, this shirt's lightweight merino fabric will work to keep you cool and dry even when you're working hard up long hills. It's even got mesh ventilation panels under the arm and along the back for extra airflow in the warmest weather, ensuring that your clothes will never hold you back when you're going for quicker times on hot days.