Our PhD Run Ultra Light Elite Pattern Micro socks aim to help elevate your running game with our favorite sock technologies. Featuring our 4 Degree elite fit system for a dialed, performance-oriented fit and Indestructawool technology for enhanced durability, our thinnest running sock can be worn perfectly with your favorite low-cut running shoes on the most demanding runs, trails, and paths. PhD is Built for Performance in the Highest Degree. 4 Degree Elite Fit System for a dialed, performance-oriented fit with flex zone at ankle joint. Indestructawool technology features a patent-pending construction method for exceptional durability and comfort. Mesh ventilation zones provide optimum moisture management and maximum breathability. Light Elite Cushioning provides maximum impact protection with targeted cushioning on the ball and heel of the foot. Designed specifically for runners. Sock Height: Micro. Virtually Seamless toe for enhanced comfort. Achilles tab designed to prevent sock from slipping down into footwear. 57% Merino Wool, 40% Nylon, 3% Elastane. Machine Wash Warm. Wash Inside Out. Made in USA of Imported Yarns.