Our Deep Space base layers feature an industry exclusive called Trizar™, a NASA Certified Space Technology woven into every fiber of this garment before it is constructed. Your body is constantly emitting heat, Trizar materials react to the infrared heat you produce and produce an individual comfort zone. Trizar captures body heat inside the garment and re-radiates it back to the user, keeping you warmer. The materials actively increase the performance of your gear without bulk / weight and expand the temperature range to increase comfort. Trizar also diffuses moisture, moving perspiration out of the garment to keep you dry and comfortable.