Made of 75% Sensura Polyester and 25% Stretch Nylon. The stretch nylon woven into the sock ensures firm support and fit in the arch, ankle, and heel, and keeps them fitting properly, without stretching out. The Sensura contains a moisture management system, channeling perspiration and moisture out of the sock where it can quickly evaporate helping keep your feet dry and healthy. Machine wash in cool or warm water and dry at low to medium setting.