These Copper Strength 20-30mmHG Knee High Spiral Weaving Premium Grade Compression Support Socks by FITDIO are designed with specially formulated spiral weaving which isolates your legs and provide optimal support & coverage. Constructed with 80% Nylon and 20% Spandex, these Compression Socks by FITDIO are perfect for Cross-Fit, Yoga, Running, Walking and general Working Outs! Our Compression Socks also aid with fluid retention, varicose veins, swelling and prolonged standing. Size Small/Medium (S/M) fits Men Shoe Sizes 8-10 & Women 6.5-8.5. The ankle circumference is 10”-11” and the calf circumference is 16”. Size Large/X-Large (L/XL) fits Men Shoe Sizes 10-12 and Women 8.5-11 with an ankle circumference of 12” and a calf circumference of 18”. The measurements provided per size are based on the Socks being worn, not laid flat. We recommend that you take your own measurements before placing your order to ensure that our Compression Socks are the right fit for you.