Klein Tools Heated Base Layer Vest is designed to be a lightweight, low-profile insulated base layer vest perfect to wear under a jacket or other outerwear. A durable, weather-resistant exterior softshell design offers ultimate comfort for prolonged wear. Designed with four total pockets and an adjustable waist cinch to keep heat in. Three heat settings can be easily adjusted with the touch of a button. Battery is a compact, palm size with a large capacity that provides great runtime