Yes, you know Smartwool socks, but do you know Smartwool's base layers? The Evie Lou crew is obsessed with them for layering in colder weather. We wear them for outdoor activities from running to biking to skiing, but they are also ideal under everything for our freeze babies, who abound here in Cleveland's winters! The top is crafted in a soft, itch-free merino wool, which naturally helps regulate body temperature, transports sweat away and cancels out odors. The top has long sleeves and a flatlock seam construction that helps prevent chafing. The fit is deliberately close; we recommend sizing up if you want a roomier fit.