For unbeatable defense against cold weather, SmartWool's NTS Mid 250 Zip T delivers with the softness, warmth, and moisture managing performance of pure merino wool. . NTS next to skin Mid 250 base layer for cold weather performance. Fine merino wool fibers provide supersoft, itch free comfort and warmth SmartWool breathes, manages moisture, regulates temperature, and naturally resists odor. Interlock knit UPF 50 for maximum protection from the sun. 10 in. center front zipper with semi locking logo slider. Shoulder panels eliminate top shoulder seams for smooth comfort when wearing a pack. Flatlock seam construction designed for chafe free comfort. Logo at left sleeve cuff. Form fit: Slim fit follows the contours of the body.