The Ultrasonic Heated Tunnel Gilet offers the best in insulation solutions. Carbon fiber heated panels are embedded into this padded body warmer to bring extra warmth and comfort to the wearer. The use of innovative heat sealed baffle fabric increases its water resistance. The S558 also has three heat settings controlled by a button at the chest. Compatible with 10000MaH, 5V Lithium Battery with USB- A connection port. Please note that a battery pack is not included.