1/4-Zip Classic Thermal Base Layer, Arctic Green HeatherThis terrific top is crafted in a soft, itch free Merino wool, which naturally helps regulate body temperature, transports sweat away and cancels out odors. It has long sleeves and a flatlock seam construction that helps prevent chafing; a short mock collar and zip closure at the chest adds versatility. The fit is deliberately close; we recommend sizing up if you want a roomier fit.