Specification Material: Cloth Color: Black Size: 13 x 10 x 2 inch Weight: 175 g, 170 g, 140 g Battery: 4000 mAH, 5000 mAH Voltage: 3.7-5 V Temperature: 45-6011. Long Heating Time: Rechargeable heated socks can equipped with 4000mAh large capacity battery, providing you with up to 10 hours enduring warmth. 22. Material: This heating socks are made of premium cotton material. Combined with ergonomic design, the socks have good breathability and excellent sweat perspiration effect, and you will feel very comfortable. 33. Multiple Heating Methods: The heated socks are designed with 3 heat settings, including high heat, medium heat and low heat, Heat socks reach a temperature from 113F to 140F. and can last up to 4 hours. 44. Upgraded Heating Design: The heating element of this pair of socks has been upgraded to a carbon fiber line heating element, and the heating line has been hidden in the position of the forefoot, so that your toes will quickly feel warm and you are no longer afraid of the cold. 55. Widely Use: For people who always felt cold of feet when winter comes. And it is also great for men and women who love hunting, skiing, ice fishing, and other winter events. We have special pocket design of placing the battery pack, give you fully comfortable whether you are walking, running or sleeping.