The Patagonia Capilene 4 Expedition Weight Zip-Neck for Men is the warmest most breathable baselayer in Patagonia's Capilene family. This synthetic baselayer will keep you dry and comfortable in winter's harshest conditions. It has a soft, stretchy feel, with a smooth jersey face that glides beneath layers and a brushed fleece interior to warm your core, wick moisture, and rest smoothly against the skin. Details include articulated, raglan sleeves for complete shoulder mobility, hidden thumb loops to ensure wrist coverage and an elongated zipper for efficient venting.