Soft, rib-knit socks made with oxygen-boosting HoloFiber® are clinically proven to increase blood flow up to 29.9%. Ideal for diabetics. Small fits sizes 7-9; Medium fits sizes 9-11; Large fits sizes 10-13. Antimicrobial 47% acrylic/38% Celliant®/13% nylon/2% spandex is machine-washable. USA.