Thermo°Cool is a thermoregulation system. It detects when your mattress needs to be heated up a bit and when it needs to be cooled down. It is often used with other types of fiber, such in the Yogabed where it is combined with TENCEL to help your mattress remain at an optimum temperature throughout the night. This mattress reduces the chances of you waking up during the night with your night clothes soaked with sweat.