The Boss Thermal Heated Base Layer is the perfect overall Winter weather gear that is designed to warm and maintain your core body temperature. It is engineered to go over a shirt but underneath a coat or sweatshirt so it can be easily concealed. It has 3 separate heat settings controlled by an included remote so you can adjust the temperature according to your needs. Low 90°F, Medium 115°F and High 135° F. The temperature setting can be controlled using the included remote control or with the push of a button located on the vest itself. The rechargeable 5V power bank provides 8 plus hours of warmth to give you all day use. It has customizable sizing (1 size fits all) using the durable 2-way locking Velcro straps to make sure every shape and size has a comfortable and snug fit. It is the perfect heating device that allows you to stay warm while you are hunting, shoveling the driveway, skiing, snowboarding, working outdoors, going for a walk or attending a concert or sporting event. Size: One Size Fits All. Color: Black. Gender: unisex. Age Group: adult.