The HT Heat Tech Vest features Alpinestars Heat Tech System which distributes perfectly balanced warmth in the coldest of conditions. The HT Heat Tech Vest features Alpinestars Heat Tech System which distributes perfectly balanced warmth in the coldest of conditions. The smart system has a double system for optimum performance in cold weather; a manual control via an LED button with three pre-set heat settings AND an automatic heating control system.The automatic heating control system has a temperature sensor embedde