Duofold Men's Midweight L/S Crew polyester-blend base-layer-underwear closure 100% Polyester (Inside) And 70% Polyester, 30% Merino Wool (Outside) Cold weather, low-impact activities Moisture control, odor resistant Machine wash cold with like colors. use only non-chlorine bleach when needed. no fabric softener. tumble dry low. remove promptly. do not iron. Jordan