Offering three-stage warmth technology, Heat Holders Unisex Twist Thermal Crew Socks boast a 2.34 Thermal Overall Grade (TOG) rating making them seven times warmer than everyday cotton socks that offer a 0.33 TOG rating. Breathable Heat Holders yarn provides high-performance insulation to block out the cold while offering superior moisture-wicking abilities so your feet stay dry. Using Heat Holders Loops an innovative knitting technology that produces a unique, extra-long-loop cushion pile to hold warm air in. Heat Holders Brushing process maximizes the amount of warm air held inside the socks for continued all-day comfort and warmth. 91% acrylic/5% nylon/3% polyester/1% elastane. One size fits most. Imported. Mens size range:7-12. Womenssize range:8-13. Colors: Black/Burgundy, Black/Grey, Brown/Khaki, Clay, Earth Brown/Mid Brown, Grey, Indigo.