75%Bamboo 25% polyester (4 Pairs in a bag) Imported CozyWow liner socks are made from 75% bamboo fiber. Bamboo fiber makes the socks breathable to keep your feet dry and cool. The 25% polyester added to the eslasticity of the socks, makes it soft, comfortable and stretchy. Designed as the invisilbe low cut socks, the socks will not show and can match with many shoes like sneakers, flats, ballet shoes, boat shoes, dress shoes, high heels, etc Anti-skidding guaranteed with silicon: Each sock has a wide anti-slip silicon grip at the heel part to prevent socks from slipping off. The socks will stay up no matter you are wearing them for walk for sports Hand wash and hung dry recommended, but can be washed in machine with low heat water and dried in dryer. Socks will not shrink and keep what they are after washing Added Value: CozyWow is a US registered brand, we provide 100% satisfaction guarantee. If you have any questions, we are here for you.