Ammonia Detector 5800G Monitor NH3 Gas Level with Alert, Kethvoz Amoniaco Medidor Detect Ammonia 0~100 PPM with 0.1ppm Resolution, Test Temperature & Humidity for Poultry Livestock House

When I opened the Box I noticed the Sensor Cover was off and the Sensor was inside of the cover.At first I though this might be intentional but as I played with it more I realized that even if I plug the sensor back in and run tests with it with no cover all I get is a 0.0ppm reading of Ammonia.I tried products that list Ammonia I even went out and bought Ammonia Glass cleaner that had high concentrations of Ammonia in it and I could not get this meter to read anything. Maybe it can read full 100% Ammonia gas from a cylinder but that would be useless for my purposes.After that I tried to put the cover back on it is covering the sensor. From the Amazon page I though that the upper part of that cap was a cover. You can see from the inside photo that the Cap has holes in it to let in Gas but the upper part cannot be separated to reveal those holes at the top. I think either they changed their mind and decided to seal the cover onto the Intake and force the user to expose the whole sensor to Gas in order to get better sensitivity OR mine was messed up in the manufacturing process. Believe me there is a seam which would look like the Intake has a cover over it but that seam is not cut through and the top cannot be removed.The other issue is that there is really nothing holding the whole Cover part to the Meter, no locking system or twist in system to hold it. I can use literally shake the cover off the meter. Also the sensor can easily drop out of it's socket. It is barely held in.I gave it Three stars instead of One because I honestly do not know if mine is an isolated case of a broken, incomplete built or defective meter.