CO2 gas Modulator 3 PackChanges the continuous flow of CO2 coming from our gas regulator hose into intermittent "Plumes" for better catch rates of host seeking female mosquitoes and midges. Pack contains Three Modulators (3 months supply). (One only shown) As a secondary benefit, as the CO2 passes through the Modulator it releases other food grade attractants (Including Lactic Acid) that are housed in the device. Other lures do not need to be used in conjunction unless there is a specific need.