In the Merino 150 Baselayer Long Sleeve Smartwool has used its lightest and most versatile material. With this merino wool/nylon mix the men's shirt convinces with increased durability, high breathability, it dries quickly and works solo worn in warmer weather or as a first layer in colder temperatures. So you can wear the long all-season shirt for men in spring, summer and autumn when hiking or mountaineering as well as in winter when skiing. Merino 150Smartwool's lightest, most versatile layer with increased durability that regulates body temperature, wicks moisture away from the body and resists odour.Core SpunMerino fibres wrapped around a nylon core. This eliminates seams &, warping and guarantees extra durability, comfort and performance.