KEEP YOU WARM WHENEVER, WHEREVER USB Charging Electric Heated Vest: Powered by any 5V/2.1A power bank, the universal USB plug is compatible with most power banks in the market. Humanized Heating Design: The humanized heating part is designed to heat the area and can be heated quickly even in extremely cold weather. Ideal for all types of outdoor activities such as snow sweeping, skiing, camping, hiking. It is also very suitable for people who always feel bone pain on cold or rainy days. 3 Heating Levels: Three heating levels can be adjusted by one button to provide a wide range of temperatures. (Energy-saving temperature is about 25 °C, comfort temperature is about 35 °C, the warm temperature is about 45 °C). Built-in Pockets: Built-in pockets are convenient for you to carry mobile power (not included).