Features: Crafted from fine fabric, comfortable to wear. Built-in USB port and inside pocket for power-bank. Turtleneck and zipper up closure to front. Two zippered side pockets keep hands warm. Cut with a slim fit. Instructions for use: 1. Vest features built-in USB port to connect the power-bank. 2. Power switch - long press the switch for 3 seconds. 3. Red light flashes - automatic heating; after 5 minutes flash, automatically adjust to the mid-range temperature level. 4. Red light - high temperature, warm. 5. White light-medium temperature, comfortable. 6. Blue light - low temperature, energy-saving. Note: The power-bank is not included.