Size Chart Built so you can test your limits. Clinically proven to improve performance, you'll feel lighter on your feet and re-energized. These women's socks increase circulation, help prevent injury, make your run far more enjoyable. The product of years of R&D, these are the best thing 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