Whether worn as a standalone on warm afternoons or as a baselayer on cool mornings, the Smartwool Merino 150 Short-Sleeve Baselayer Top keeps you comfortable as you hike, run, bike, and climb. Its lightweight merino wool construction wicks moisture, repels unwanted odors, and delivers thermal regulation. Plus, the merino fibers are wrapped around a nylon core for added durability so you can confidently wear the top through your preferred activity.