Smartwool M CLASSIC THERMAL MERINO BL 1/4 ZB Men’s zipper shirt: With the Smartwool M CLASSIC THERMAL MERINO BL 1/4 ZB you decide when it’s time to finish. The inner layer of Merino wicks moisture away from the body and regulates body temperature. You can wear it on its own or as a base layer in colder weather. The special First Layer cut prevents irritation and abrasions. Smartwool M CLASSIC THERMAL MERINO BL 1\/4 ZB