Like New Edited from Tracksmith, see below: "Our best-selling Brighton Base Layer features an engineered Merino mesh that’s more open around your core, with a closed knit on the sleeves for a bit more warmth in your extremities. We designed it specifically as a training base layer to be worn under a mid-layer or a jacket, but its seamless construction gives it a comfortable, flattering fit that’s not too tight to wear all by itself. Soft, breathable, and odor-resistant, the Brighton Base Layer is ideal for cold runs when you need to layer, and can also be worn on its own. Stunningly soft and not at all scratchy, Merino wicks moisture and regulates temperature. It’s almost completely impervious to odor, even if you never choose to wash it. Unlike synthetic wicking materials, Merino stays warm even when it’s wet. Our Brighton Base Layer is constructed seamlessly to reduce any chance of chafing because it is intended to be worn against your skin." 16.5 Micron Merino Wool Blend 52% Wool, 28% Nylon, 20% Polyester Chest 30" Body Length 24" Sleeve 25.5"