Vaiden Astronaut Workout Apparel utilizes Outlast® Phase Change technology - an innovative way to enhance your body's ability to manage temperature. The technology was originally developed to help astronauts regulate their temperatures in space. As your body works, heat is transferred and absorbed into tiny polymer shells within the fabric called Thermocules™. These Thermocules™ then release heat toward and away from skin as needed, keeping you at an optimal temperature. The fabric acts like a battery, absorbing heat from your skin during workouts and releasing the heat back to you after workouts. The technology is comparable to ice in water. When placed in water, ice will absorb heat from and cool the water as the ice melts. Our technology partner holds over 96 patents related to thermally adaptive technology. They offer the only Phase Change technology that carries the Certified Space Technology seal of approval. In addition, the American Society for Testing has both tested and approved Thermocule™ Technology. This organization was founded in 1898 and is one of the largest standards development organizations in the world.