Goodknight Gold Flash Liquid Vaporizer Combi Contents: 1 Unit each of electric plug-in machine and anti-mosquito liquid vaporizer cartridge * Visible Flash vapours on Flash mode Releases Flash vapours for the first 30 minutes and then, automatically switches back to normal * On Flash mode, releases Flash vapours for 30 minutes and then, automatically switches back to normal * Every four hours switch from normal mode to flash mode Normal mode when there are few mosquitoes & Flash mode when there are many mosquitoes.