XL Heated Base Layer Vest. Heated vest has a lightweight design and is the perfect base layer to wear under any jacket without restricting movement. A durable, weather resistant exterior softshell design offers ultimate comfort for prolonged wear with four total pockets and an adjustable waist cinch to keep heat in. Four built-in heating panels on left and right front chest, upper back, and lower back that are designed to keep your core warm. Compact battery has a slim design with a large capacity. The vest offers three heat settings: high with 4 hours of runtime, medium with 6 hours, and low with 12 hours, all adjustable with a simple touch of a button.