SmartWool Men's Heathered Rib Socks 61% Merino Wool, 37% Nylon, 2% Elastane Knit in USA Sock Height: Crew Style: SW0SW164 Medium Cushion: Medium cushioning for impact absorption and long days on your feet Machine Wash Warm Gentle Cycle. Do Not Bleach. Tumble Dry Low. Do Not Iron. Do Not Dry Clean.