Automotive Scope Applications' GREENThing is a hand-held automotive five gas fuel efficiency analyzer powered by AC and DC, and has an internal rechargeable battery. It is very sensitive and doesn't require venting to the outside. Electronic self-calibration is automatic. Compatible with gasoline, CNG and propane, the analyzer can display air/fuel or Lambda, and can be used to test diesel emissions. There are 255 memory locations to store data.