Made with Aweartech 37.5 technology this wool-blend vest features fabric that is triggered by your body temperature to either warm or cool itself depending on the situation. The active particles permanently embedded in the yarn capture heat from your body's infrared energy to speed evaporation and cool itself if there is moisture vapor (sweat) present, or retain that heat to keep you warm when no moisture is present. Absorbs odor molecules that are removed when cleaned. Stretch mesh fabric is integrated throughout to ensure maximum mobility and comfort.