This easy-to-use and affordable CO2 PPM Monitor/Controller is a tool that any indoor gardener can use to maintain CO2 levels derived from generators as well as bottled systems. Unit accurately measures CO2 levels from 0- 5,000 PPM (parts-per-million). Customers simply plug in their CO2 generator to the CO2 PPM Monitor/Controller and it automatically maintains their specified level. This device works with any 120-volt CO2 generator or valve and carries a three-year warranty.