The 5V 10,000mAh power bank will help keep you warm. As? It is an external battery which, when connected to our Nuclor line jackets and vests, becomes a heat generator. In fact, this battery will energize the heating wires inside the clothing, thus contributing to the generation of heat. The duration varies according to the type of heat desired, we assure you that you will no longer suffer from the cold during your days on the pitch.