so it will tell you if you're in closed loop, open loop, if the O2 sensor is faulty, if you're above or below 14.7 AFR - you will not know if it's 13.5 or 11.5 AFR for example, the output of the O2 is the same in that case, same goes for lean but in that case it's easier.
Instead of this i would rather purchase an led based one as the response time is faster and the information is the same (there's really no point of having numbers displayed, you would know right away when the PCM is in closed loop and when in open loop using the led based ones, there's really no information past that point as the O2 sensor is not providing anything more that in the close range of 14.7)
at $187 i'm sorry but the price is stupid - for $12 more you can get an innovate LC1 with a wideband O2 (included) and computer logging capabilities and software or get the edelbrock wideband o2 meter for (i think) something like $130 (that also comes with a sensor).
this is from the Jet manual for this (read page 3 and 4 in this doc for examples of almost useless information to be displayed
http://www.jetchip.com/DownloadFile.asp?File=pdf/howto/Air%20Fuel%20Monitor/Air_Fuel_Monitor.pdf)
Reading the Air/Fuel Meter:
The Oxygen Sensor must be at operating temperature before you will get any reading
on the screen, normally it must reach 600 degrees F before you will get an accurate reading.
Once up to operating temperature at idle and cruise the air/fuel ratio will cycle up and down,
this is normal, it is the vehicles PCM trying to maintain a perfect air/fuel ratio. This ratio is
called stoichiometric, at this ratio all of the fuel and oxygen is burned. During acceleration
you will notice that the meter will move to a richer mixture, this is also normal, by accelerating
you have increased the amount of fuel the sensor is reading.
EDIT:
This one is cheaper and seems to be independent from the stock unit (although, it seems like a narrow band as well). I also trust Edelbrock more than Jet, but that's because I dont know Jet and I have heard a lot about Edelbrock... Could be due to me not knowing the brand (I guess Jet could also be a well established brand, but I dont know).
that's edelbrock one i was talking about and it is wideband.