This product is relying on a combined application of 5-aminolevulinic acid and corresponding light sources, a new technology that selectively destroys tissues through photodynamic reactions to improve skin conditions. Different combinations of light have different effects on the skin. Red light: Wavelength 640nm, penetration 1-6mm, beneficial to skin regeneration, relieve pain, and activate active ingredients. Blue light: wavelength of 423nm, penetration of 1mm, is beneficial to calm the skin, improve sensitive muscles, and stabilize the skin. Yellow light: wavelength of 583nm, penetration of 1-2mm, is beneficial to improve flushing, erythema, relieve flushing symptoms, and prevent skin lesions. There are 4 kinds of combination lights: red-blue combination light, red-yellow combination light, blue-yellow combination light, red-blue-yellow combination light, combination light has two or three functions.