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, this shirt wraps Merino around a nylon core for added durability while still keeping the comfort of ultra-soft Merino next to skin. Smartwool has added smooth flatlock seams to help minimize chafing and offset shoulder and side seams to lie smoothly beneath pack straps. Performs well on its own in warmer temps, or layers up easily when cooler weather rolls in. 87% Merino Wool, 13% Nylon Core. Merino 150: Smartwool's lightest, most versatile layer with enhanced durability and ultimate breathability. Quick drying, it works as a solo layer in warm weather or as a baselayer in cool weather. Core Spun: Merino fibers wrapped around a nylon core for added durability while still keeping the comfort of Merino next to skin. Slim Fit. Raglan sleeve design removes shoulder seams. Flatlock seam construction designed to eliminate chafing. Machine Wash Warm Gentle Cycle. Do Not Bleach. Tumble Dry Low. Iron Low. Dry Clean. Garment Weight: 170 g = 6 oz. Knit in Vietnam.