Review on UEi Test Instruments CO71A Handheld Digital Carbon Monoxide Detector, Portable CO Meter with 0-999ppm Range, Visual and Audible Alerts, CO Monitor Tester + Battery Included by Christopher Gotcher

Although it's not approved for use on airplanes I sometimes use it to check the cabin for carbon monoxide. I bought this after my newly purchased used aircraft was put on an annual report and found that there was significant erosion around the exhaust port which required a cylinder replacement. As far as this product is concerned, it is indeed very accurate. Your first "test" will probably be sticking it under the car's exhaust pipe to see if it works, which is really quick! (Note that after testing you will need to put it in clean air for about 30 minutes to deoxidize it. On my plane, on the ground in Houston (near many oil refineries), I noticed that there were 2 to 5 parts ppm (parts per million) carbon monoxide. In the air and flying over Arkansas it's gradually approaching 0 ppm so I'm sure it works fine. Even though it's not certified for aviation use, it is certainly more accurate and timely than the useless "black dot" indicator stickers which are slow to respond at best and essentially useless if over 6 months old (causing a false security alert?) Get one and you will glad you did!, I almost forgot - took this to a friend's recently bought used house and checked the vents with the heat on and found about 125ppm carbon m onoxide. The HVAC worker stopped by and discovered that the furnace manifold was cracked, which is quite dangerous. My girlfriend (and pregnant wife) was eternally (pardon the pun) grateful that I tested the vents. Take one, a little pricey but the alternative is much, much worse.