Size Chart Built so you can test your limits. Clinically proven to improve performance, you'll feel lighter on your feet and less fatigued. These smooth men's socks increase circulation, help prevent injury, make your run far more enjoyable. The product of years of R&D, these are one of the best things to put between you and every impact. Features: - Encircles your muscles more than 300 times in graduated compression - Technical performance knit delivers exceptional air flow - Seamless toe-closure for maximum comfort - Anatomically padded cushioning, anti-blister, anti-hotspot - Supremely smooth yet durable - 85% Polyamide (Nylon), 15% Elastane - 20-30 mmHg graduated compression - Low-maintenance ownership-machine wash and dry