The ActionHeat Women's 5V Battery Heated Base Layer Shirt redefines cold-weather comfort with advanced heating technology and lightweight design. Engineered to deliver warmth without the bulk, this base layer features a Tri-Zone heating system that targets the chest and upper back to maintain a comfortable core temperature. Its flexible ActionFlex fabric allows unrestricted movement while providing soft, breathable warmth ideal for layering under outerwear. With a 5V rechargeable power bank that can also charge mobile devices, you get convenience and performance in one. Adjustable heat settings and easy touch-button control let you stay comfortable through every cold-weather activity.