Koukento Carbon 6000 for Light Therapeutic Devices, No. 10 Pieces, Use 1 Pair for Light Therapeuty, and burn at high temperatures and emit isolated light by discharging the carbon electrode tip. This allows you to obtain a visible overall light and radiant temperature of the continuous spectrum that resembles the suns rays required for treatment. Therapeutic carbon is the main ingredient of high-purity carbon (carbon), and therapeutic carbon is a core electrode with trace amounts of metal elements in the core, and the composition changes the issue spectrum. Source: Kazuaki Kuroda (1999) "Separate Edition, Visible General Light Therapy Theory and Examinations" Foundation Light Research Institute