The Hotronic XLP One PFI 50 Heated Ski Socks are a perfect solution for any skier who has been plagued with cold feet who does not want bulky battery packs attached to their boots. Two Lithium-Ion Batteries can deliver up to 11 hours of consistent heat. The low-profile battery easily connects up above the cuff of your ski boot to stay out of the way as you spend your day on the mountain with warm and cozy feet. The XLP One is machine washable (remove battery packs) and air dry for a fresh feeling every time you hit the mountain. Includes 2 Lithium-Ion Batteries, US and European Charger, 70% Nylon/20% Spandex/10% Marino Wool, Machine Wash/Air Dry, Fantastic Wicking Ability, Consistent Heating Power, Perfect for Diabetics or People with Reynauds Syndrome, Warranty: One Year, Material: Wool/Synthetic Blend, Type: Ski, Weight: Light, Model Year: 2020, Product ID: 503829, Model Number: 01-0100-306-2, GTIN: 9120070760657