SmartWool PhD Run Ultra Light Mini Socks 54% Merino Wool, 42% Nylon, 4% Elastane Knit in USA 200 needle construction provides highest knit density while maintaining ultra light weight Virtually seamless toe 3.75" overall height - Sock Height: Mini Style: SW0SW165 Machine Wash Warm Gentle Cycle. Do Not Bleach. Tumble Dry Low. Do Not Iron. Do Not Dry Clean.