Spring skiing or summer camping? The year-round Smartwool Men's Classic All-Season Merino Base Layer Long Sleeve is game for either. With Core Spun technology, Smartwool's wrapped lightweight Merino around a nylon core for added durability, while still keeping the comfort of ultra-soft, responsibly-sourced Merino next to skin. Smartwool also added smooth flatlock seams to help minimize chafing and offset shoulder and side seams to lie smoothly beneath pack straps. No matter the season or the activity, this base layer is made for it. FeaturesLightweight Merino jersey fabric uses a recycled nylon core to increase durability while still keeping 100% Merino wool next to skinFlatlock seam construction and offset shoulder and side seams designed to increase comfort and minimize chafingSide seams wrap to front for body-enhancing fit