The ActionHeat Mens 5V Heated Base-Layer Long-Sleeve Shirt is created to keep you warm for hunting or outdoor work, without the use of bulky layers. This ActionHeat heated shirt can be worn under a jacket or outer layer, and has 3 built-in heating panels that are strategically placed on the chest and upper back to warm your bodys core temperature. FAR infrared heating and ActionWave reflective technology deliver hours of heat and comfort. The system utilizes 5V rechargeable batteries and comes with a powerful 6000mAh power bank that can also be used to charge your phone, tablet, or any USB device. Touch-button adjustment provides warmth for 2 hours on high, 3 hours on medium, and 4.5 hours on low. The ActionHeat 5V Heated Base-Layer Shirt for men includes a power bank and USB charging kit. 92% polyester/8% spandex. Ultrafine carbon-fiber heating panels. Machine wash. Imported. Sizes: S-2XL. Color: Black. Type: Base Layer Tops.