Great for cool-weather hikes and spring tours, the Icebreaker Men's Everyday Half-Zip Top keeps you warm, but not too warm, when you're pushing hard in the outdoors. Merino wool naturally regulates your temperature so you don't get chilled or overheat, and it's antimicrobial so after a full day of grunting uphill, it isn't going to smell like a ninth-grade gym locker room. The 1/4 zip front lets you ditch some heat when you need to. Flatlocked seams reduce the chance of chaffing, and raglan sleeves help to maximize the range of movement in your arms.