Goodknight Gold Flash is INDIA?S MOST POWERFUL LIQUID VAPOURISER. It consists of a mosquito repellent cartridge (refill) and clip-on electronic machine. This vapouriser system is powered by Gold Flash technology which has 2 modes - Flash and Normal Mode. Use Flash Mode when there are more mosquitoes, and Normal Mode when there are less mosquitoes. Visible powerful Flash vapours instantly spread across the room and drive away mosquitoes, even the hidden ones. Flash mode releases visible vapours for 30 minutes every 4 hours.