The Pentair Haffmans CO2 /O2 Gehaltemeter, type c-DGM is an accurate CO2 , O2 and TPO quality control device. The Pentair Haffmans CO2/O2 Gehaltemeter, type c-DGM measures dissolved CO2 content and dissolved O2 content in liquid, O2 in gases, CO2 purity in gases, and the Total Package Oxygen measurement in a beverage package.