The Thermic Heat Fusion One + S-Pack 2400 Heated Socks Set includes everything you need to warm up your ski days. The Fusion One socks are thin for enhanced ski performance with strategic padding on the shin, reinforcement on the heel, and a protective toe, giving you the support you need for an athletic feel. And with the included S-Pack 2400 batteries, these socks offer up to 14 hours of heat, keeping your toes warm and nimble for extended sessions on the hill.