Spring skiing or summer camping? The year-round Merino 150 base layer long sleeve is game for either thanks to the body temp regulating and no-stink properties of Merino. Featuring Core Spun technology, Smartwool wrapped Merino around a nylon core for added durability while still keeping the comfort of ultra-soft Merino next to skin. Smooth flatlock seams help minimize chafing and offset shoulder and side seams to lie smoothly beneath pack straps. . . . 87% Merino Wool, 13% Nylon Core. . Slim Fit. . Merino 150 is Smartwool 194113127874 32096700047 SW016042