Spring skiing or summer camping? The Classic All-Season Merino Base Layer Long Sleeve is game for either. With our Core Spun technology, we've wrapped lightweight Merino around a nylon core for added durability, while still keeping the comfort of ultra-soft, responsibly-sourced Merino next to skin. We added smooth flatlock seams to help minimize chafing and offset shoulder and side seams to lie smoothly beneath pack straps. Select colorways feature a more responsible plant-based-dye technique. No matter the season or the activity, this base layer is made for it.