The Photon or Bio Stimulation Monochromic Red Light wavelength is 660Nm. Some mats - Flexible Purple, 5-gem and 7-gem mats - use Next Generation Photon lights. Each lamp has one Visible Red Monochromatic 660 Nm and two invisible Near-Infrared and/or Mid-Infrared 800-1200 Nm light emission diodes. Red light is excellent for photon therapy as it can penetrate several millimeters deep into the skin's surface layer and has been shown to improve microcirculation. In addition, numerous studies on Pubmed demonstrate the healing potential of visible red light for nerve regeneration. There are many studies that discuss the benefits of red light for immunity, nerves, and joint health.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4126803