The ActionHeat Rechargeable Battery Heated Cable Knit Slippers are stylish, warm, and comfortable. Made out of a wool blend, their unique design and fuzzy lining make them an excellent choice for lounging around the house on a cold winter night. They are powered by rechargeable 5V batteries and can last up to 5 hours.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 side of the slipper. Turn On - Press and hold the touch-button control on the sock for 3 seconds. Press the button to cycle through the heat settings. Features: Comfortable heated soles Soft polyester lining provides warmth, comfort, and versatility Strategically placed heating elements use ultra-fine fibers for optimal heating performance An integrated heating system located on the bottom of the foot Heating panels encapsulated with a thermal seal provide additional durability & moisture protection Estimated Heating Times: High (Red): 150F - 3.5+ Hours Medium (White): 130F - 4+ Hours Low (Blue): 115F - 5+ Hours Material Contents: Polyester: 74% Wool: 20% Nylon: 6% Lining: Polyester 100% Includes: (2) ActionHeat Rechargeable Heated Cable Knit Slippers (2) 5V Volt Lithium-Polymer Rechargeable Batteries (1) 24" Dual Battery Charger Kit