General Tools MMD4E Digital Moisture Meter, Water Leak Detector, Moisture Tester, Pin Type, Backlit LCD Display With Audible and Visual High-Medium-Low Moisture Content Alerts, Grays eBaydiy Tools

10 reviews for General Tools MMD4E Digital Moisture Meter, Water Leak Detector, Moisture Tester, Pin Type, Backlit LCD Display With Audible and Visual High-Medium-Low Moisture Content Alerts, Grays eBaydiy Tools

1. 

   hellolani – March 18, 2026

   Great product; it measures wood from 5 – 50% +/- 3% accuracy
   We were getting hardwood floors installed – or so we thought – when the installers notified us that they could not do the installation because the wood in our house had acclimated to 6.4% moisture and our subfloors were at 12.8% moisture. The installer found a leak in our water softener line which we got fixed the next day. Unfortunately, we had no way of knowing (ourselves) when to call the installer back. Hence, we purchased this meter.As far as we know, it works great. We aren’t too concerned with the overall accuracy of the instrument, +/- 3% is just fine for us as we’re looking to compare the difference between two materials in our home (assuming the error is consistent between those readings). The resolution of the meter is 0.1%.Other things you might want to know:- It comes with it’s own 9v battery.- It measures wood between 5 – 50% and 1.5 – 33% for other building materials.- It has a hold feature which allows you to save the current reading so you don’t have to keep the meter jammed in the material you are measuring.- It beeps to let you know when it is done measuring. (Although, you can turn this off. We did accidentally and then figured out how to put it back on. We don’t know why, but it has 8 different tones from which you can select.)- It has a toggle button between measuring wood and concrete (or other building materials).- The instruction manual is easy to read and follow. They come in English, French, and Spanish.- It uses a two pin system to measure the electrical resistance of the material between the two pins. This is then calibrated against moisture content to give you the reading as a percentage. This means that it will make two small pin holes in the wood you are trying to measure. Therefore, if you are concerned about the holes, consider a “pinless” moisture meter, which are much more expensive.The instruction manual lists other uses such as testing the moisture content of powders (for any scientists out there who need to measure such things for making standard solutions from scratch) and to test the dryness of a wall or furniture before painting or finishing. It also shows instructions for how to track down a leak using the meter. There’s a funny picture in the instructions with the caption “be careful not to hurt your hands on the pins.” Although, I did “test” the moisture content of my husband’s leg. Don’t worry, I didn’t draw blood.Overall, for the price, the features, and the product functionality (so far), I would say this is a great buy. Also, we got it shipped quickly via Amazon.com. It arrived two days after we purchased it. Yay!UPDATE (7/31/2010): The pins broke when we were testing some brazilian walnut – one of the hardest woods out there. But I read in the instruction manual that pins were replaceable. I emailed General Tools through their website and got a quick email back. Less than a week later, I had two new prongs FOR FREE in my mailbox. Customer Service was AMAZING! The replacement prongs are much better than the ones that came with the meter. The new ones are shaped like little cones and have worked great on the harder woods.

2. 

   K1WJK – March 18, 2026

   Top notch item
   This is a great product for the price. Amazon got this to me in a timely manner. My general reason for buying this item was to measure firewood. As far as I can determine, it is very easy to operate, functions as stated, and I believe I made the correct choice for my purposes.I will state here that I did not read all of the reviews, but I read enough of them to decide upon this item.These are my technical observations for those who may have doubts reading some of the other reviews. I wondered about the battery life, so I made some checks. Using my Heathkit IM-2215 digital multimeter, I found that the current draw in the on (no measuring) position using the 200 ma scale, was a steady 5.8 ma. Using the lowest scale of 2 ma, the current draw was 5.8 ma with a fluctuating least significant digit (LSD). In the off position, using the lowest 2 ma scale, I note a current draw of .000 ma. So, my dear friends, if there is any current draw, it would have to be in the micro-ampere range. It probably draws less than my digital clock in the car! I am not worried about the battery life. If you doubt these studies, let me inform you that I have been a licensed radio amateur since 1962. Trust me, I know what I’m doing.Depending on the species of wood, most woods (previously kiln dried) will absorb in a humid environment, in the neighborhood of no more than 13 to 14 % moisture. I got this information from my local lumber producer. I looked at numbers worked out with a formula.I found that interesting, so I probed some timbers down cellar in this nearly 100 year old home. Wood posts and floor joists showed some variation, but in general were 13 to 14 % moisture in my cellar having a humidity level of 80 to 90 percent. My highest joist readings were 15.9 and 16.0 per cent. I have one of those Acu-rite digital devices on the cement floor. The temperature was 61 degrees. The upstairs humidity is currently running at 58 %, which is not ideal. I have been considering a dehumidifier.I hope this information allays any fears you may have purchasing the MMD4E moisture meter. I love it!

3. 

   Halena I. – March 18, 2026

   For professionals
   It seemed to work ok but when I got my house tested by a professional the results were very different. I was easy to use however, you do have to make holes in the wall. Its battery life seemed good as well as calibration capability.I would only use if I was a professional. Otherwise do not waste your time.

4. 

   Ulan – March 18, 2026

   Very accurate and helpful for detecting moisture issues
   This moisture meter has been extremely helpful and easy to use. I used it to check different areas near the wall and floor, and it provided clear and consistent readings. You can immediately see the moisture level on the screen, which makes it very convenient for quick inspections.The device feels solid and well made. It responds quickly and gives accurate results, which is especially useful for detecting hidden moisture problems before they turn into bigger issues. I like that it has different indicators, so it’s easy to understand whether the moisture level is low, medium, or high.Overall, this is a very practical tool for homeowners. It helped me better understand the condition of my floors and walls, and I’m glad I had it on hand. I would definitely recommend this product to anyone who wants a reliable and easy-to-use moisture detector.

5. 

   MacDogMom – March 18, 2026

   Works GREAT. Takes the guesswork out of selecting logs to burn.
   LOVE IT!I rely on my wood stove to heat during winter. This is a wonderful help in deciding which piece of wood to burn at that time.Sometimes a little moisture is OK, but sometimes you want it dry to heat in a hurry.

6. 

   pulkit – March 18, 2026

   It’s the best from all th meters available in market

7. 

   Mukuka Mubanga – March 18, 2026

   Easy to use with timber

8. 

   Abdulla Alazeze – March 18, 2026

   Very useful and we found something not new damage in the wall we can’t see it but with this we discover it .

9. 

   Alonso Sansores – March 18, 2026

   Excelente artículo y servicio. Muy fácil de usar.

10. 

    Vossi – March 18, 2026

    Die Funktion ist einfach und gut ablesbar, doch eine Beschreibung ohne deutsch ist schlecht zu gebrauchen.Das gesamte Ergebnis ist aber gut.