My husband said to me some time ago that it smells like cat pee in the hallway. We have two of these copies. I have searched all if I have to find some wet spots on the carpet or the tile. Unfortunately without success. Recently, I smelled it but himself and went again unsuccessfully searching. Then I discovered a puddle on our parquet floor that I saw just in time and was able to eliminate and prevented greater damage on the ground. After some research, I came because this urine detector and see, numerous stains and little laughter could be seen in the dark! My two cats, incidentally, have free passage and additionally clean toilets. I feel this behavior inexplicable. In any case, the detector is highly recommended and great was that the same batteries are included so that you could make an immediate effect on the search. My batteries were incidentally not yet.