For Amethyst mats, it is 3.66 x 102 W/m2. These mats have a minimum efficiency of 93% in the wavelength range of 5-14 microns. This wavelength range is best utilized by the human body. Almost 80% of this energy is transferred at two "amethyst peaks" at 7 and 12 microns. For mixed gemstone mats, it is approximately 3.7 x 102 W/m2. These mats have a minimum efficiency of 93% and can operate effectively within a wider range of 4-20 microns. Approximately 50% of the heating energy is transferred at two amethyst peaks, which occur at 7 and 12 microns.