The ActionHeat(TM) 5V Wool Battery Heated Socks are the perfect blend of quality and comfort for any winter activity. Featuring a a maximum temperature of 150F that can last up to 5 hours, these heavy duty socks are designed to warm the core body temperature. This heated sock set comes complete with built-in heating panels and are made with ActionFlex material that provides lightweight warmth, comfort, and versatility. How to Use: Power Up - Charge the provided ActionHeat 5-Volt batteries Plug-In - Connect the batteries to the USB cords located in the pocket on the top of the sock Turn On - Press and hold the touch-button control on the sock for 3 seconds. Press button to cycle through the heat settings Estimated Heating Times: HEAT BLAST (Red): 150F - 3+ Hours Medium (White): 130F - 4+ Hours Low (Blue): 100F - 5+ Hours NOTE: Recommended to use low or medium settings. Heat Blast should not be used for more than 5 minutes at a time Includes: (2) ActionHeat Wool Blend Socks w/ Heated Toes (2) 5V Volt Lithium-Polymer Rechargeable Batteries (1) 24" 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 Heat-trapping fabric provides maximum warmth, comfort, and versatility. Touch-Button Control Technology (3 settings) Power System: 1 amp Battery Voltage: 5 Volt Colors Available: Black Machine Washable using provided mesh wash bag only (gentle cycle) Heats 5+ Hours Unisex Fit