Smartwool Men's Classic All-Season Merino Long Sleeve Base Layer Shirt - Spring skiing or summer camping? The year-round Men's Classic All-Season Merino Base Layer Long Sleeve is game for either. With Core Spun technology, Smartwool has wrapped lightweight Merino around a nylon core for added durability, while still keeping the comfort of ultra-soft, responsibly-sourced Merino next to skin. Additionally, there are 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. Fit: slim - intended to follow the contours of the body; Lightweight Merino jersey fabric uses a recycled nylon core to increase durability while still keeping 100% Merino wool next to skin; Flatlock seam construction and offset shoulder and side seams designed to increase comfort and minimize chafing; Side seams wrap to front for body-enhancing fit; 88% Merino Wool, 12% Nylon; Style: SW016952;