Made of 80% Bamboo, 15% Polyester, 5% Elastic; Bamboo fiber socks are breathable and durable to keep your feet dry and cool.Material: 80% Bamboo, 15% Polyester, 5% Elastic. Fabric made from bamboo is extremely soft. Many people who cannot wear hemp or wool directly on their skin because of allergies experience no irritations from fabric made with bamboo. Widely considered as a more renewable source than cotton, materials made from bamboo are becoming more and more sought after, especially by green-conscious individuals.One of the most unique qualities of bamboo fiber is that it is Sweat-absorbing. Bamboo fabric can sweat-absorbing even after multiple washes. Cushioned Sole: Extra comfort and moisture absorption makes your feet breathable and comfortable.Small Fit for US Boys Shoe Size 6, Women??s Shoe Size 4-7.5;Medium Fit for US Men??s Shoe Size 7-9, Women??s Shoe Size 5-10;Large Fit for US Men??s Shoe Size 9-11.5, Women??s Shoe Size 11-13;X-Large Fit for US Men??s Shoe Size 12-15.Additionally, bamboo itself can take in up to three times its weight in water, and its fabric has the ability to pull moisture away from the skin, allowing it to evaporate. Therefor bamboo socks are going to help keep your feet dry. The toe area design is free from any irritating seam.Anti-Slip: The big Y design on the heel makes sure the socks stay in place no matter how busy you are. The unique fabric is perfect all year round. It will keep your feet cool in warmer months and help insulate heat during colder temperatures. Bamboo socks are going to allow you to walk in comfort all day long, and you no longer have to worry about chafing or irritation.Washing tips: Machine Wash.Bamboo fiber will be much softer after the first wash. We suggest you wash them before you put them on. Compares the cotton socks, bamboo socks look smaller but they are super stretchable. The fabric is durable and sustains its softness even through multiple washes.