Icebreaker made its Men's Aero Crew Shirt to keep you comfortably cool on hot summer days whether you're running, working out, or enjoying a yoga session. Featherweight merino wool makes up the majority of this shirt to regulate your body temperature and naturally resist odor over an extended time without a wash. A bit of nylon keeps this shirt durable for hikes and trail runs, and flatlock seams reduce chafing on long workouts.