Our best-selling pillow technology is now available in a topper for total-body cooling. The CarbonCool LT + OmniPhase Topper uses phase change material to continually regulate temperature. Here how it works. When you fall asleep, your temperature drops, releasing body heat into your sleep environment. OmniPhase phase change material microparticles move that heat away from the body by changing phases and releasing energy. The temperature falls, and you are actively cooled all night as the PCM maintains the optimum sleep temperature. To further the cooling properties, activated carbon infused in the foam creates a pathway to filter heat away from your entire body. Plus, precision ventilation in a unique zoning pattern increases airflow and correctly aligns the spine.