... The light activates the whitening gel and oxidizes the pigment of the teeth through dentin tubes in the shortest ... there are three choices of light source (Blue, Blue & red, Red). Four power outputs and adjustable setting time for different preference ... ,let patient feel relieved.Three LED light sources: Blue, Blue&Red, Red.Teeth whitening system Specifications:Broad Spectrum: 430nm ~ 490nm & 620nm ...