Spandex Pull On closure Machine Wash 94% Acrylic 5% Polyester 1% spandex Polar Extreme insulated thermal socks - keep your feet warm and comfortable during the extreme cold winter weather; Warmth - the yarns used have excellent thermal properties and when combined with the specialized manufacturing techniques we employ, the result is the super warmest and soft thermal sock that holders your foots heat; Comfort - you deserve comfortable crew socks and these are them. Just feel the inside of these heavily brushed lined socks and you can imagine how comfortable they will be on your feet; Performance - with the inherent moisture management of these socks combined with the thermal properties the result is a fantastic performing sock: the warmest thermal sock imaginable. No more cold feet!