SmartWool Women's PhD Run Ultra Light Low Cut Socks 49% Merino Wool, 47% Nylon, 4% Elastane Knit in the USA Run-specific fit - Virtually Seamless toe 200 needle construction provides highest knit density while maintaining ultra light weight 2.25" overall height - Sock Height: Low Cut Style:SW0SW195 Machine Wash Warm Gentle Cycle. Do Not Bleach. Tumble Dry Low. Do Not Iron. Do Not Dry Clean.