This incredibly reliable, extremely affordable CO2 monitor effortlessly maintains your CO2 levels between 1300 and 1500 PPM. It can be used with any CO2 generator or bottle regulator on the market. Green LED display allows you to check your CO2 levels at a glance. Powerful 5 Amp relay allows you to control pumps or other high amperage devices with the monitor. This little gem features a highest quality Senseair brand CO2 detector, resulting in an incredibly low failure rate. This is a monitor that will work out of the box and keep working for many years to come. Oh, and it's self calibrating too.