Gerbing 7V Wool Heated Socks. Heats the entire bottom of your foot. Microwire heating elements deliver evenly distributed heat. Moisture-wicking Wool Blend fabric. Special long cut pulls over your calf to fit any boot or shoe. Touch-button temperature control. Includes: Two 7V Wool Heated Socks. Two 7V 2,200 mAh Batteries. 7V Dual Charger. Estimated Heating Times: High (Red): 140°F - 3 Hours. Medium (White): 120°F - 5 Hours. Low (Blue): 100°F - 7 hours. Note: These socks get hot. Follow instructions and use them carefully.