Made with AWEAR-TECH 37.5 technology, these slacks feature fabric that is triggered by your body temperature to either warm or cool you 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 you if there is moisture vapor (sweat) present, or retain that heat to keep you warm when no moisture is present. Suit separates let you choose jacket and pant sizes separately for a custom fit.