Outlast® is a thermoregulatory fabric originally applied to the spatial suits of astronauts. The technology enclosed inside makes use of phase change materials. That is, inside there are millions of spheres made with a special wax that merges at the temperature of 36 degrees. As soon as the body temperature begins to grow technology comes into action, absorbing excess heat. When the temperature begins to drop, the spheres present inside the material resume to consolidate and release the accumulated heat. Thus the ideal temperature remains constant and increases the regularity of your sleep.