Made in China Combustion Analyzer and Printer, Digital Display Screen Type LCD Touchscreen, Maximum Carbon Monoxide Measured 4,000 ppm, Maximum Oxygen Measured 21 Percent v/v, Minimum Oxygen Measured 0 Percent v/v, Selectable Fuel Options Bio Fuel, Coal, Coal Town Gas, KOKS, LPG, Natural Gas, Oil #2, Oil #6, Propane, Minimum Carbon Monoxide Measured 0 ppm, Maximum Combustion Efficiency 100 Percent, Minimum Combustion Efficiency 0 Percent, Maximum Excess Air Measured 999 Percent