I live in a Co-Op apartment building that self-manages all of its repairs. This year we have had a major issue issue with moisture working its with through the mortar of our three course brick building. The building will be 100 years old in 2015. We have questions about whether the moisture visible on our walls and ceiling was a piping problem or water from the elements. Also when we could see the staining caused by the moisture, we wondered if it was a new or old problem. Well, this very inexpensive and reliable meter has given us a tool to track the moisture in the wall and check for new moisture after a heavy rain or not. I convinced the Board of our Co-Op to purchase two more so that we would have enough on hand to monitor the highest frequency of issues at any one time. Mind you, though, that I found the only 6 volt battery that would work was the Duracell brand. I had tried Eveready unsuccessfully.