Product review (5 stars): Great fast responding meter
I actually purchased this unit to replace a similar but older model CO2 meter the TIM 8 which had been in service for five years .  It's used to monitor ventilation in ambulatory surgery center. The old unit stopped working  but was accurate for the most part although had some odd features such as strange musical alarms and a very complicated and nonintuitive user interface.  The TIM 10 is simple to set up and seems to respond a bit faster to changes in CO2 level than the old unit.  The LCD display is large and very readable, although a backlight would have been nice. Although you don't buy this gauge for its humidity meter it should be noted that the humidity readings are about 5% lower then a true calibrated standard hygrometer, but this may be nitpicking. The temperature gage is accurate .  As I noted before, my original  unit lasted five years but at $150 a pop I would expect to get somewhat longer service out of this one. There is a lamp that flashes inside the unit to provide the infrared light source and that appears to be had failed in my old unit.  Nevertheless I'm still giving this five stars since they are no comparable units for such a competitive price point