The Therm-ic Slim Universal (10 000 mAh) portable powerbank for heated vest is a powerful external battery for your heating jacket. A USB port is provided to plug the cable directly into the jacket. The battery is charged directly with a micro-USB port (USB cable supplied, wall charger not included). Simply connect and slide the compact and lightweight battery inside the pocket of your jacket and this is it. Blue LED lights indicate the charger’s remaining capacity so you will never be caught unprepared for your outdoor activities.