The Testo 310 residential combustion analyzer sets a new standard in affordable flue gas analysis with its rugged housing, simple design, and advanced sensor technology. With only a 30 second zeroing start up time, the Testo 310 is ready to test quickly, using simple display icons to clearly show the current measurement functions. Fully featured and priced right, the Testo 310 residential combustion analyzer provides exceptional value and complete capabilities in combustion testing and furnace efficiency. You can easily perform complex flue gas analysis, maintenance and safety checks, and furnace efficiency confirmations. The stainless steel probe and cone-stop are perfect for residential boiler efficiency applications and can be used for accurate heating adjustments, ensuring that you can get it right the first time, and every time. With five different fuels to select from (natural gas, propane, fuel oil 2, biomass 5%, and wood 20%), it provides the flexibility you need for all your tuning needs. Also included is a wireless IR printer, allowing your measurement data to be easily captured and documented.-O2, CO (with built-in NOx filter), CO2-Undiluted CO (CO air free)-Ambient CO-Draft & pressure-Temperature (flue & ambient)-Combustion / flue gas efficiency & excess air