What Our Gearhead(R) Experts Are Saying: "I've been using this top for early morning runs. It's super breathable, and the merino-TENCEL blend keeps it feeling dry and fresh even when I'm working hard. It's soft, light, and doesn't cling, so it's my go-to for sweaty sessions."Whether we're heading into a high-output trail run or stretching it out in a hot yoga studio, the Smartwool Active Long Sleeve keeps us feeling cool, dry, and confident. This performance top combines the natural thermoregulation and odor resistance of merino wool with the moisture-wicking and cooling power of Tencel lyocell, so we stay comfortable through every rep, step, and stride. Designed with movement in mind, the soft, lightweight knit layers easily or works great on its own, while reflective details add a touch of safety for early morning miles. From tempo sessions to recovery hikes, this is a staple in our rotation.