Bests & Worsts Reviews from Amazon

tested this device at exhaust of car & water heater for 10+ minutes...no reading, alarm or response. reset device, repeated tests. Device just sits there, no change from "0", pressing peak button shows "0". Device should take a reading every 15 seconds & 30 ppm should be lowest it can detect per manual. Called support, was told I was wrong, device works. Informed device needs following exposures to record any peak measurements or alarm: 36ppm for 50 consecutive hours! 400ppm for 8 minutes. Reading is based on a scale, higher the ppm, sooner before it registers a reading. Hours must be consecutive, so a device turning on and off will no register a low reading. Customer service hung up on me while I was talking. I was dissatisfied, but not being rude or disrespectful. This device seems fine for those who are ok being slowly poisoned.