Battery pack with heated ski socks. Enjoy winter exercise to the full with the Therm-ic Powersocks Set. Each Therm-ic Powersocks Set includes a set of heated socks and a pair of S-Pack batteries. S-PACK 1200 batteries will give you up to 14 hours of warmth. The socks are technical and will keep your feet warm thanks to the composition of natural and synthetic fibres. Ski warmly this winter!