... , simple, practical, safe, you just need continuously use 3 to 5 times, each time 20 minutes, ... oxidize the pigment in teeth.Item specificsteeth whitening home use lightavailable for logo print 1, Fixed Voltage:DC6V ... , LED colour:blue4, Wavelength:460~465nm5, Continuous use:48 hoursAdvantages1.it's high in quality and reasonable ... etc.) hot teeth whitening light for home use, teeth whitening kit light