80% cotton Material Composition: Louak&Hiron low cut socks are made of 80% cotton and 20% spandex for good elasticity. Size & Care instruction: Our no show socks fit for US men shoe size 6-9/ US women’s shoe size 8-11. Machine wash in cold water and Air dry. DO NOT dry clean, iron, bleach. Moisture wicking and breathable: Mesh knited on low cut top and super-thin design makes our cotton no show socks more breathable and moisture-wicking, keeps your feet dry and fresh Non Slip: Our brand new socks not only add anti-slip silicone strips on heel, but also attach anti-slip silicone around cuff, which makes the socks much harder from sliding down when walking or running No Show: Low cut on the top makes your feet completely invisible in lots of different style shoes, such as sneaker, sport socks, some loafers and low tops shoes, but not all low top shoes.