Make sure your feet stay warm and cozy with the ActionHeat(TM) Wool Rechargeable Heated Socks. These socks are designed with rechargeable lithium ion batteries to provide you with up to 10 hours of warmth perfect for camping, hiking and much more. ActionHeat(TM) panels are strategically placed to provide you with warmth while wool material delivers a cozy fit while keeping your feet a comfortable temperature. How to Use: Power Up - Charge the provided ActionHeat 3.7V batteries Plug-In - Connect the batteries to the cords located in the pocket on the top of the sock Turn On - Press and hold the power button on the battery for 3 seconds Estimated Heating Times: High (Red): 140F 4+ Hours Medium (Orange): 120F - 6+ Hours Low (Green): 100F - 8+ Hours Includes: (2) ActionHeat Wool Blend Socks w/ Heated Toes (2) 3.7 Volt 2.2AH Lithium-Polymer Rechargeable Batteries (1) Dual Battery Charger Kit Specs: Built-In heating panels strategically placed on the top of the toes use advanced ultra-fine fibers to provide superior heating performance Battery Voltage: 3.7 Volt Colors Available: Black Machine Washable using provided mesh wash bag only (gentle cycle) Heats 8+ Hours Unisex Fit