Stay warm even when the temperature dips with the ActionHeat™ Cotton Rechargeable Heated Socks. These outdoor socks are designed with revolutionary technology to provide you with up to 10 hours of warmth perfect for camping, hiking and any outdoor adventure. ActionHeat™ panels are strategically placed to provide you with a comfortable feel while cotton fabrication offers a cozy and soft feel. 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 Cotton 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