Icebreaker made its Men's BodyFit 200 Oasis Short-Sleeve Crew out of merino wool to regulate your body temperature so you'll stay cool when you're working up a sweat under the sun and warm when you dip into the shade of the trees. It's also anti-odor so this shirt stays fresh after a week of backpacking across Europe. Offset shoulder seams keep your shoulders comfy under that heavy backpack too.