Be warm within minutes with Woof Wears battery-operated Heated Gilet, warming the lower back, tummy and chest for core-body warmth. Simply plug a mobile phone powerbank into the USB cable located in the pocket, press and hold the button for three seconds to begin heating and use the button to switch between three heat settings: high, medium and low. Even without the battery, he Heated Gilet features a cosy lining, perfect for layering in the winter Powerbank sold separately.