CO Carbon Monoxide Detector with Digital Display & Loud Alarm - Battery Operated, Waterproof for Home, RV, and Camping Safety

This is an excellent product. I frequently use a propane cook stove in a small area and I need to monitor the CO. This is an actual measuring device as well as an alarm. I have tried to use home CO alarms and the were not useful, even the ones that have some digital readout. I paid over $100 for another brand of CO sensor that was highly recommended for pilots of small aircraft. It worked, but it didn't show readings until an alarm level was reached. This Sensorcon unit starts reading at 1 ppm. Listed as accurate to +/- 2ppm, I have no reason to doubt that.I don't have equipment to test this thing for accuracy but after several years of very frequent use, I am convinced that it works reliably and is likely far more accurate that my use requires.I was not aware that a freshly opened can of coffee grounds contains a high level of carbon monoxide. I open a can of coffee in the vicinity of my unit and its alarm started beeping. I didn't know what the cause was, but eventually I put it near the coffee and the reading went above the upper limit of the device. It seemed to damage the unit. I could not get it to work again, but the next morning it seemed to be functioning normally again. Keep it away from car exhausts especially when the car is cold and just being started, and keep it away from freshly open coffee grounds and you will be very happy with this CO sensor.