Description As Wirecutter's top pick for the best thermal underwear, the Aspect Base Layer Long Sleeve Shirt is "a city-to-trail shirt" and their "most versatile pick." They capture what we love most about this base layer—it's incredibly versatile, incredibly comfortable and works well no matter where the day takes you. It feels great on your skin and keeps you warm, dry and comfortable, plus it has industry-leading durability. It's cut long to stay tucked in when skiing, and it has discreet thumb holes to keep your sleeves in place. Pair this shirt with the Aspect bottoms in full length or 3/4 length. Product Features All the benefits of Merino wool: resists odor, wicks moisture, protects from the sun, breathes well and regulates temperature Natural and sustainable Merino wool reinforced with (m)Force Technology for increased durability, dry times and recovery Versatile mid-weight base layer that's warm but not too warm Flatlock seams Backpack-friendly raglan construction Discreet thumb loops keep sleeves in place when needed Printed neck label Removable care label Long cut for layering that stays tucked in Fabric Details 84% Merino wool, 16% nylon Soft 180 GSM (m)Force Merino 18.5M wool Size M weight: 8.3oz Care: Machine wash on warm or cold, hang dry. Do not bleach or dry clean. Iron on low wool setting. Learn more. Sizing/Fit Joey (in Bark Camo and Terra Cotta) is 6'2" wearing a Large. Nate (in Cement Dye) is 5'11" wearing a Large. Danila (in Black) is 5'10" wearing a Large. Fits close to the body Extra length for more coverage Not sure what size to order? See our size guide.