NDI 6 in 1 Non-invasive Moisture Meter Pinless Humidity Sensor Drywall/Gypsum Board/Cement Board/Cork/Hardwood/Mildew Index

It does exactly what you hope, just understand that the way these work are effected by metal, so if what you're testing has any metal at short depth behind your test area, it will register as 30+%

Easy to use and accurately detects the problem behind the wall.

Bought it and was skeptical that it wouldn’t work but it told us one of our windows had mildew and when we got it check it - it sure did!!!

Me resultó muy útil para detectar pérdidas de agua

Great value and accurate. Matches readings to a $600 meter within 2%. Easy to use and read.

We bought this in April and it worked for a few months but then started having issues with batteries losing charge VERY quickly. Thought it was the batteries themselves but it was the product. It is now five months and won't turn on at all. Reached out to seller and nothing...look for a better product!

I had the unfortunate mishap of having a leak , and it was able to confirm which areas I had a leak without puncturing my dry wall or floors. My plumber used it as week to confirmWhich area was more impacted than others, and having professional use it, made me feel much better over the trusted product. It’s light weight and easy to store.

Found high levels of mold in my rental bathroom. Thrilled because I thought mold was structural and it was just in rubber parts of shower and floor so I cleaned those places and no more problem!