Our bestselling 72-Hour collection is crafted from a New Zealand merino wool with a nylon core so you can toss it in the washing machine. The ultimate travel shirt in our arsenal, it does just as well as a merino wool base layer as it does on its own as a casual long sleeve t-shirt—perfect for adventures that call for packing light and staying comfortable. Even after three days hours of constant wear, this shirt still passes the smell test thanks to the naturally odor-resistant and moisture-wicking properties of merino wool.