Ski sock with a number of foot (shin, ankle and instep) reinforcements for total comfort. Practical and versatile, it’s perfect for skiing.Developed in partnership with X-Technology. The Therm-ic PowerSocks Heat Uni Sets include a pair of heated socks and a pair of S-Pack 1200 batteries. Socks: Ski sock with a number of foot (shin, ankle and instep) reinforcements for total comfort. Practical and versatile, it’s perfect for skiing. Developed in partnership with X-Technology. Materials: Polyamide 45% (nylon), Acrylic 38%, Polypropylene 10%, Polyester 5%, Elastane 2% X-Technology fibers: Xitaloft 38%, Nylon 32%, Robur™ 13%, Mythlan™ 10%, XITANIT® 5%, Elastane 2% Batteries: The S-Pack 1200 is the most common battery used by our customers, making it the most popular among thousands of winter sports enthusiasts. Warm feet for up to 14 hours Pack comes with a USB charger Wall charger not supplied