Ultra challenges need ultra socks, the Salomon S/LAB Ultra Knee Socks have been engineered for ultra distance runs. Designed with bio ceramic fibres to help improve and stimulate micro blood circulation to fight muscle fatigue. The light compression elastic fibres and EXO sock construction provide support and has exceptional moisture wicking properties. The knee length height provides compression for your calves and will prevent debris from entering the socks. They offer a secure fit and silicone grip stripes around the forefoot to keep your socks in place during even the most challenging terrain.