About WOOTSHU: WOOTSHU has always been a leader in the development and manufacture of heating clothing . Recognized by everyone, we focus on the research and development of heating clothing series. As the saying goes,'happiness is better than wealth' Why Choose Lightweight USB Charging Heated Vest, Electric 5V Heated Jacket Clothes Warmer?This uniquely designed heating vest is equipped with a USB port and can be used in conjunction with a mobile power supply. It is easy to use and does not require special batteries. The built-in 5 heating panels can provide enough heat (located on the back and waist that are most susceptible to cold) to keep warm and comfortable in the cold winter. How To Use Insert the USB port to 5V power source, we recommend 5V/2.1A power bank.(Note:Power bank need to purchase separately) Long pressing the switch of the vest for 3 seconds to turn it on/off Short pressing the switch to change the heating mode 3 Heating Level Setting： Red-highest temp（55℃/131°F~65℃/149°F） White-medium temp（45℃/113°F~55℃/131°F） Blue-lowest temp（40℃/104°F~45℃/113°F） Please Note: 1. Please take off the power before wash. 2. Prohibit the use of products while sleeping. 3. Do not dry cleaning, can't be screwed after water washing. 4. Do not use this with pacemakers, pregnant women, young children and those who insensitive to heat. NOTE: This heated vest can be hand-washed or machine-washed, Machine washing must use a laundry bag, the strong centrifugal force of the washing machine may break the cable.