General Tools MMD4E Digital Moisture Meter

by General Tools

Product Description

From the Manufacturer

Ideal for use in woodworking, building construction and agriculture industries. The MMD4E is also a invaluable to the restoration field. Ideal for locating moisture in carpets and sub-flooring.

Product Description

Generals ultra-sensitive Digital Moisture Meter easily detects hidden leaks in wood, concrete, plaster and carpet. Providing accurate moisture level readings make this moisture meter great for new home inspections, locating roof leaks or even selecting dry lumber at the yard. Ideal to use in woodworking, building construction, agriculture restoration and floor-laying. Used to check wood, drywall and concrete before painting, sealing or treating and locate and identify water leaks in roofs, floors and walls. Features LED display, wide measuring range, strong stainless steel pins, audible alarms and battery status indication. Display will show the moisture content in Percent Moisture Content directly. Ergonomically designed and CE approved.

Product Details

• Product Dimensions: 9.5 x 5.5 x 1.5 inches
• Shipping Weight: 7.2 ounces (View shipping rates and policies)
• Shipping: This item is also available for shipping to select countries outside the U.S.
• ASIN: B00275F5O2
• California residents: Click here for Proposition 65 warning.
• Item model number: MMD4E
• Batteries: 1 9V batteries required. (included)
• Average Customer Review: 3.8 out of 5 stars  See all reviews (52 customer reviews)
• Amazon Best Sellers Rank: #884 in Home Improvement (See Top 100 in Home Improvement)
  • #2 in Home Improvement > Power & Hand Tools > Measuring & Layout Tools > Scanners & Testers > Moisture Meters

Customer Reviews

Most Helpful Customer Reviews

88 of 90 people found the following review helpful:

5.0 out of 5 stars Great product; it measures wood from 5 - 50% +/- 3% accuracy, July 12, 2010

By 

D. L. Pascual "hellolani32" (Indianapolis, IN USA) - See all my reviews
(REAL NAME)   

Amazon Verified Purchase

This review is from: General Tools MMD4E Digital Moisture Meter (Tools & Home Improvement)

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.

29 of 31 people found the following review helpful:

4.0 out of 5 stars Good Meter with a Long Power-On Delay, November 20, 2010

By 

James O. Mccorison - See all my reviews
(REAL NAME)   

Amazon Verified Purchase

This review is from: General Tools MMD4E Digital Moisture Meter (Tools & Home Improvement)

I bought the General Tools MMD4E Digital Moisture Meter to check the moisture of some flooring and trim moulding for house I am building. At the price of this product, I don't expect much in the way of absolute accuracy. Instead what I want is relative accuracy. In other words, I don't care if the wood has 8% or 10% moisture content. What I want to see is, what does the wood do over time. Once the reading stops dropping, the wood has mostly gotten as dry as it is likely to get in its present location. I tested the meter by taking a variety of readings to see if I could reproduce a giving reading. I went from dry wood to wet and back to dry. It seemed to be able to reproduce readings with a reasonable reliability.

The meter has a peculiarity that I think is responsible for another reviewer thinking his meter was broken, resulting in a 1-star rating. If the meter has not been turned on for a while, you have to hold down the on/off button for 4-5 seconds to turn the unit on. I've used a number of products which require you to hold down the power button for a prolonged period to prevent turning it on accidentally, but nothing as long as this meter. To make matters worse, the documentation says nothing about this feature. I can easily see why some people might think their meter is broken. A strange twist on the on/off is that if you turn the meter off, then turn in right back on again, you only have to push the power button for about a second for it to turn back on.

I rated this 4-stars because of the accuracy Vs resolution of the display. Why do they have a display with a resolution of 0.01% on a meter with an accuracy of +/- 3%? In trying to reproduce the same reading multiple times I typically saw +/- 0.5%. Realistically the meter should not display readings to a tenth. Sadly, many people do not bother reading directions, and as a result they may believe that the meter is far more accurate than it actually is. (The skeptic in me wonders if that was the intention of the marketing department.)

Now if only the meter would dry some of my trim boards that are at 25% moisture down to 10% so I can start trim-out. :)

25 of 28 people found the following review helpful:

5.0 out of 5 stars hydrometer, February 28, 2010

By 

J. gerth "chefjeff" (missouri) - See all my reviews
(REAL NAME)   

Amazon Verified Purchase

This review is from: General Tools MMD4E Digital Moisture Meter (Tools & Home Improvement)

i don't know how it is for lumber, but this has been great for firewood. makes it super easy way to figure out what wood to use first. highly recommended!