1) With 'Double Heater' system designed, you can curl up eyelashes firmly and keep eyelashes of natural finish for a long time. 2) The light indicator is designed on the back side of the curler - when the indicator turns from "purple" color to "pink" color completely (It usually takes 1 to 2 minutes (at room temperature 25ºC) for this process), then you can use it to work.) 3) Powered by one "AA" Alkaline Battery (LR6) only