Color | Gray |
---|---|
Brand | General Tools |
Product Dimensions | 9.5"W x 1.4"H |
Battery Description | Alkaline |
Lower Temperature Rating | 32 Degrees Fahrenheit |
Mounting Type | Surface Mount |
Operating Humidity | Varied |
Voltage | 9 Volts |
Manufacturer | General Tools |
UPC | 012301860924 716080037835 885312937219 885265551395 885367884865 681035414477 069060294668 031112659039 885898031110 522536779064 971483008299 031113382226 |
Global Trade Identification Number | 00885265551395, 00681035414477 |
Part Number | MMD4E |
Item Weight | 5.6 ounces |
Country of Origin | China |
Item model number | MMD4E |
Batteries | 1 Product Specific batteries required. (included) |
Is Discontinued By Manufacturer | No |
Size | Pin Type |
Style | Digital Pin Type, Visual & Audible Alerts |
Pattern | Digital Moisture Meter |
Shape | Drywall |
Power Source | Battery Powered |
Item Package Quantity | 1 |
Measurement System | Metric |
Usage | Inside; Amateur, Inside; Professional |
Included Components | Moisture meter, batteries, extra pins |
Batteries Included? | Yes |
Batteries Required? | Yes |
Battery Cell Type | Zinc Carbon |
Description Pile | Alkaline |
Warranty Description | 1 Year |

Amazon Prime Free Trial
FREE Delivery is available to Prime members. To join, select "Try Amazon Prime and start saving today with FREE Delivery" below the Add to Cart button and confirm your Prime free trial.
Amazon Prime members enjoy:- Cardmembers earn 5% Back at Amazon.com with a Prime Credit Card.
- Unlimited FREE Prime delivery
- Streaming of thousands of movies and TV shows with limited ads on Prime Video.
- A Kindle book to borrow for free each month - with no due dates
- Listen to over 2 million songs and hundreds of playlists
Important: Your credit card will NOT be charged when you start your free trial or if you cancel during the trial period. If you're happy with Amazon Prime, do nothing. At the end of the free trial, your membership will automatically upgrade to a monthly membership.
Buy new:
$29.96$29.96
Ships from: Amazon.com Sold by: Amazon.com
Save with Used - Like New
$18.16$18.16
Ships from: Amazon Sold by: Amazon Resale

Image Unavailable
Color:
-
-
-
- To view this video download Flash Player
-
-
-
-
-
-
-
8 VIDEOS
-
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
Learn more
Return this item for free
We offer easy, convenient returns with at least one free return option: no shipping charges. All returns must comply with our returns policy.
Learn more about free returns.- Go to your orders and start the return
- Select your preferred free shipping option
- Drop off and leave!
Learn more
Return this item for free
We offer easy, convenient returns with at least one free return option: no shipping charges. All returns must comply with our returns policy.
Learn more about free returns.- Go to your orders and start the return
- Select your preferred free shipping option
- Drop off and leave!
Bundles with this item
Purchase options and add-ons
Color | Gray |
Brand | General Tools |
Product Dimensions | 9.5"W x 1.4"H |
Battery Description | Alkaline |
Lower Temperature Rating | 32 Degrees Fahrenheit |
About this item
- HUMIDITY SENSOR: Our handy meter tool can quickly determine what level of remediation is needed to keep your family safe from black mold. High levels of dampness that go untreated are the leading cause of harmful fungus growth in the home.
- WATER LEAK DETECTOR: Finding the moisture content in your wood or drywall is the first step in early prevention. Continuously check and test suspicious water stains around the house so you can determine whether the area is wet or has already dried. Low, medium and high moisture tones and on-screen icons, Reading HOLD button
- MOISTURE READER: The mold test features large 0.3" high digits in a backlit LCD for quick and easy detecting. Our mildew scanner includes extra 8mm stainless steel pins, a protective cap that doubles as a calibration checker, and a “9V” battery.
- MOLD TESTER: For an accurate test read, stick the stainless steel pins into the surface of what you're measuring. The gauge has a broad range of 5 - 50% for wood and 1.5 - 33% for building materials such as concrete and drywall.
- GENERAL TOOLS: We're a recognized leader in designing and developing specialized precision tools dedicated to delivering exceptional customer service. We encourage artisans and DIYers to work smarter, measure better, and repair more productively.
Frequently bought together

Frequently purchased items with fast delivery
Product guides and documents
From the brand

-
Innovative Product Development
We provide craftspeople and artisans with a broad assortment of specialized tools to enhance productivity and inspire creativity.
-
New and Featured
-
Best Sellers
-
Woodworking
From the manufacturer



Pinpoint Accuracy
Pin meters find moisture spots more quickly and accurately than pinless meters that can only test broad, flat surfaces
Replaceable Pins
Easily replace any bent or curled pins with the PIN3 replacement pins
Easy to Read LED Screen
Includes a hold button to freeze and hold readings
![]()
MMD4E
|
![]()
MMD7NP
|
![]()
MMD950
|
![]()
MM8
|
![]()
RHMG650
|
![]()
Replacement Pins for MMD4E & RHMG650
|
|
---|---|---|---|---|---|---|
Customer Reviews |
4.5 out of 5 stars 14,283
|
4.4 out of 5 stars 3,867
|
4.4 out of 5 stars 281
|
4.3 out of 5 stars 767
|
4.0 out of 5 stars 62
|
4.5 out of 5 stars 312
|
Price | $29.96$29.96 | $49.99$49.99 | $185.25$185.25 | $45.67$45.67 | $199.08$199.08 | $13.89$13.89 |
Deep Read Pins | ✓ | no data | ✓ | no data | ✓ | ✓ |
Deep Sensing Probe | no data | no data | ✓ | no data | no data | no data |
Pinless | no data | ✓ | ✓ | ✓ | ✓ | no data |
Measures Moisture | ✓ | ✓ | ✓ | ✓ | ✓ | no data |
Backlit LED Display | ✓ | ✓ | ✓ | ✓ | ✓ | no data |
Videos
Videos for this product
1:38
Click to play video
How this tool helped me save money on damp repairsFurnishing Solutions
Videos for this product
0:06
Click to play video
Customer Review: Great tool for measuring moistureLee A Perron
Videos for this product
1:08
Click to play video
Demo & Review of General Tools Moisture Meter!Sammie Finds
Videos for this product
1:07
Click to play video
Pin Style Moisture meterDwood Studios / Dwood Reviews
Videos for this product
2:01
Click to play video
Used for 5 years to detect Moisture in flooring ReviewSouthern Palette
Videos for this product
2:29
Click to play video
Testing This General Tools Moisture MeterUnmatched Value
Videos for this product
1:16
Click to play video
My experience with the General Tools Moisture MeterObsessed Woodworking
Product information
Technical Details
Additional Information
ASIN | B00275F5O2 |
---|---|
Customer Reviews |
4.5 out of 5 stars |
Best Sellers Rank | #619 in Tools & Home Improvement (See Top 100 in Tools & Home Improvement) #1 in Moisture Meters |
Date First Available | July 19, 2008 |
Warranty & Support
Feedback

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
Share:
Found a lower price? Let us know. Although we can't match every price reported, we'll use your feedback to ensure that our prices remain competitive.
Where did you see a lower price?
Fields with an asterisk * are required
Product Description
General’s 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.
Top Brand: General Tools
Compare with similar items
This Item 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 | Recommendations | ||||
Try again! Added to Cart | Try again! Added to Cart | Try again! Added to Cart | Try again! Added to Cart | Try again! Added to Cart | |
Price | -40% $29.96$29.96 List: $49.95 | -7% $27.98$27.98 List: $29.99 | $49.99$49.99 | -17% $24.99$24.99 List: $29.99 | $39.95$39.95 |
Delivery | Get it as soon as Friday, Apr 18 | Get it as soon as Friday, Apr 18 | Get it as soon as Friday, Apr 18 | Get it as soon as Friday, Apr 18 | Get it as soon as Friday, Apr 18 |
Customer Ratings | |||||
Sold By | Amazon.com | Mecurate Instrument | Amazon.com | Thousandshores Inc | Cascadia Innovations |
power source | Battery Powered | Battery Powered | Battery Powered | — | — |
battery quantity | 1 product specific, 1 9v | 2 aaa | 1 9v | — | 3 aaa |
operating humidity | Varied | 0-100% | — | 10-90% | — |
mounting type | Surface Mount | Wall Mount | Wall Mount | Wall Mount | Tabletop |
Important information
9 volts
Customer reviews
Customer Reviews, including Product Star Ratings help customers to learn more about the product and decide whether it is the right product for them.
To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyzed reviews to verify trustworthiness.
Learn more how customers reviews work on AmazonCustomers say
Customers find the moisture meter works well and is easy to use, taking less than a second to read and being particularly effective on hardwood floors. They appreciate its value, noting it has saved them thousands of dollars, and consider it a helpful tool for various projects. The accuracy and build quality receive mixed feedback - while some find it extremely precise and reliable, others report inaccurate readings and durability issues with bent pins.
AI-generated from the text of customer reviews
Customers find that the moisture meter works well and produces consistent results, with one customer noting it performs flawlessly on various materials.
"...The price was reasonable and it still works like new, 3 yrs after purchase." Read more
"Very good quality for the price point. Worked well on sheetrock areas" Read more
"...This meter can take a beating over time and still keep on working. Extremely good on battery life as well...." Read more
"...This moisture sensor was reasonably priced and worked very well...." Read more
Customers find the moisture meter easy to use, with quick readings taking less than a second, and one customer noting its simple 3-button operation.
"...you the range of information that other meters out there can, but it's simple and it does exactly what it's supposed to...." Read more
"...Its accuracy, versatility, and ease of use make it an invaluable asset for identifying and addressing moisture issues quickly and effectively...." Read more
"...- The instruction manual is easy to read and follow. They come in English, French, and Spanish. -..." Read more
"Works well, easy to use, affordable" Read more
Customers find the moisture meter effective at identifying moisture levels, particularly useful for checking firewood moisture content and detecting damp areas.
"...and heats with firewood, this device is very handy to determine optimum moisture content levels before stocking my woodshed with our winter..." Read more
"...features a wide moisture detection range, allowing me to accurately assess moisture levels in various materials, from wood and drywall to concrete..." Read more
"...on the back of the device (which is great), this means my ceiling is not very moist. Obviously that was good news...." Read more
"...Affordabile Ideal for Detecting Deep Moisture – Since the pins penetrate the material, they are more effective at detecting moisture..." Read more
Customers find the moisture meter offers good value for money, with several mentioning it saved them thousands of dollars, though some note that more expensive models perform better.
"...The price was reasonable and it still works like new, 3 yrs after purchase." Read more
"Very good quality for the price point. Worked well on sheetrock areas" Read more
"...This moisture sensor was reasonably priced and worked very well...." Read more
"...Affordabile..." Read more
Customers find the moisture meter to be a useful tool that comes in handy for various tasks, with one customer specifically noting its value for woodworkers.
"...Its accuracy, versatility, and ease of use make it an invaluable asset for identifying and addressing moisture issues quickly and effectively...." Read more
"Super useful item. Works so good that it broke the news to me that the "seasoned" firewood I bought for $100 was in fact, not seasoned at all." Read more
"Useful - but qualitative not quantitative. -..." Read more
"This has been very helpful in determining if a stain on the wall is from a leak. Measures moisture in dry wall and wood...." Read more
Customers have mixed experiences with the moisture meter's accuracy, with some finding it extremely precise and consistent across different areas, while others report readings that are not as accurate as expected.
"...Since the General Meter was accurate and did work I went ahead and kept it also. I gave it 4 stars instead of 5 due to the probe tips." Read more
"...If the wood has less than 5% moisture content, the meter doesn't give any reading at all, so I when I tried to test it on a piece of kiln-dried wood..." Read more
"...It always seemed to be accurate as well, when compared to similar models from other brands that co-workers used." Read more
"...Its accuracy, versatility, and ease of use make it an invaluable asset for identifying and addressing moisture issues quickly and effectively...." Read more
Customers have mixed opinions about the moisture meter's build quality, with some finding it well-made and reliable, while others report questionable quality and that it doesn't last.
"Very good quality for the price point. Worked well on sheetrock areas" Read more
"...Inconsistent Performance on Hard Materials – meter struggles with denser woods or materials that resist penetration, leading to unreliable readings..." Read more
"Reliable. If anyone buys firewood from a supplier this is definitely needed to test the dryness of the wood before they dump it...." Read more
"Probes seem flimsy" Read more
Customers report significant durability issues with the moisture meter's pins, noting that they bend after a few uses, break easily, and are flimsy.
"...UPDATE (7/31/2010): The pins broke when we were testing some brazilian walnut - one of the hardest woods out there...." Read more
"...Too bad. I would pay more for this meter. It seems fine except the low quality pins. $15 for replacements? Sure, if they were stronger......" Read more
"...It came with 2 extra pins and a battery. Not bad for the price of a moisture meter." Read more
"...to "insert" but don't twist or bend while inserting, the results are broken pins and no reading." Read more
Reviews with images

Moisture sensor was reasonably priced and worked very well
Top reviews from the United States
There was a problem filtering reviews. Please reload the page.
- Reviewed in the United States on January 27, 2025Pattern Name: Digital Moisture MeterVerified PurchaseAs a person who lives in rural Wisconsin and heats with firewood, this device is very handy to determine optimum moisture content levels before stocking my woodshed with our winter supply.
The price was reasonable and it still works like new, 3 yrs after purchase.
- Reviewed in the United States on March 28, 2025Pattern Name: Digital Moisture MeterVerified PurchaseVery good quality for the price point. Worked well on sheetrock areas
- Reviewed in the United States on January 16, 2025Pattern Name: Digital Moisture MeterVerified PurchaseI purchased this to check recent water damage in my house and it worked well but the tips seem fairly delicate. I ended up also purchasing a moisture meter from Klein that read from the surface rather than probes that needed to be pushed into the piece you're checking. Since the General Meter was accurate and did work I went ahead and kept it also. I gave it 4 stars instead of 5 due to the probe tips.
- Reviewed in the United States on March 24, 2025Pattern Name: Digital Moisture MeterVerified PurchaseReliable. If anyone buys firewood from a supplier this is definitely needed to test the dryness of the wood before they dump it. If firewood is to green to burn it can easily be sent back. I got stuck with 2 cords of wood that needed another 18 month to season. If I had this I would never accepted the delivery.
- Reviewed in the United States on January 2, 2025Pattern Name: Digital Moisture MeterVerified PurchaseI worked pest control for 4 years and was in thousands of crawlspaces in that time. I always had this meter with me to get moisture readings in the subfloor system while doing termite inspections and just general crawlspace inspections for moisture mitigation. This meter can take a beating over time and still keep on working. Extremely good on battery life as well. It may not give you the range of information that other meters out there can, but it's simple and it does exactly what it's supposed to. It always seemed to be accurate as well, when compared to similar models from other brands that co-workers used.
- Reviewed in the United States on March 6, 2025Pattern Name: Digital Moisture MeterVerified PurchaseWe had some roof leaks and needed to check where they were to air them out. This moisture sensor was reasonably priced and worked very well. As you can see in the picture, it will light up red when there is substantial moisture in your walls. Very happy with the product and would recommend (not happy about my roof leaks!).
5.0 out of 5 starsWe had some roof leaks and needed to check where they were to air them out. This moisture sensor was reasonably priced and worked very well. As you can see in the picture, it will light up red when there is substantial moisture in your walls. Very happy with the product and would recommend (not happy about my roof leaks!).Moisture sensor was reasonably priced and worked very well
Reviewed in the United States on March 6, 2025
Images in this review
- Reviewed in the United States on April 18, 2024Pattern Name: Digital Moisture MeterVerified PurchaseThe General Tools MMD4E Digital Moisture Meter is an indispensable tool for anyone dealing with moisture-related issues. From the moment I started using it, I was impressed by its accuracy and ease of use. Whether I'm checking for water damage in walls, floors, or ceilings, this moisture meter provides precise readings with just the press of a button.
What sets the MMD4E apart is its versatility and reliability. It features a wide moisture detection range, allowing me to accurately assess moisture levels in various materials, from wood and drywall to concrete and plaster. Plus, its compact size and ergonomic design make it comfortable to hold and use for extended periods.
Overall, the General Tools MMD4E Digital Moisture Meter is a must-have tool for contractors, homeowners, and DIY enthusiasts alike. Its accuracy, versatility, and ease of use make it an invaluable asset for identifying and addressing moisture issues quickly and effectively. I highly recommend it to anyone in need of a reliable moisture meter.
- Reviewed in the United States on June 4, 2013Pattern Name: Digital Moisture MeterVerified PurchaseI recently noticed a small crack in my ceiling that has a large brown outline around it. The brown outline is clearly water damage, but while the crack is definitely new, I cannot tell if the water damage has always been there or not. I bought this device to help me to determine if I need to call in a professional.
The product arrived today, as expected. It was in its retail packaging, which is a clamshell. You'll need scissors to open it up. A 9v battery was also inside the clamshell. I'm not sure why the change, but I'm really happy that companies are now including batteries with their toys.
So I took the meter out of the packaging and put in the battery. No screws to take out or anything. The battery cover just clips back on.
The device couldn't be much easier to use. There are only 3 buttons..
1. Power. Hold this to turn the moisture meter on and off
2. Mode. Press this to switch between wood and "construction material" mode.
3. Lock/Sound. Press this toggle "lock" of the display in case you want the percent to stay on the screen. Hold this to toggle whether or not the device beeps (you probably don't want it to beep).
I'd be testing my drywall ceiling, so I put the moisture meter into "construction material" mode. I was hoping I wouldn't need to jam it into my ceiling to see the results, so I first tested a part of the ceiling I knew did not have a leak. The meter read about 3%. I moved over to the brown spot and pressed the needles against the ceiling (I didn't push in) and, depending on where I was along the brown spot, the reading ranged from about 2%-6%. According to the guide on the back of the device (which is great), this means my ceiling is not very moist. Obviously that was good news.
Then I started to worry that the device would not function right if it wasn't fully pushed into the ceiling. I really did not want to put holes in the ceiling, but I figured that in the best case, I'd need to paint over the brown spot anyway, so two little holes couldn't hurt. So I jammed the needles into the ceiling in a few places and getting a consistent reading was not easy. In a few of the spots, the percentage changed from between 1%-2%, then from 7%-10% and back again. I wasn't moving the meter -- it just could not decide the moisture level. Now, I understand the science behind the device (at least I think I do), so I get that I could have been moving it a little or maybe I was there was some movement within the ceiling so the circuit was not continuously completed.. I'm really not sure. I tried a few different places in the ceiling, and in the end, I have slightly more confidence that there is not a leak on the ceiling, but I am not sure about it. Hopefully if there was a leak, the device would be more decisive in telling me about the moisture.
Overall, I think I'm happy about the purchase, but only because I got a little extra confidence for $30, which is probably less than I would have paid an "expert" to come and check it out. If you're a home inspector or contractor who will be charging people for your use of a moisture meter, I would look into the more expensive options, but for a homeowner who does not want to pay $100+ for a device you'll probably use 2-3 times in your lifetime, this one will give you a little more information than you currently have.
In summary, very easy to use, but I'm not completely confident in its ability to give reliable results.
Top reviews from other countries
- SamarthReviewed in India on August 23, 2019
5.0 out of 5 stars Good product
Pattern Name: Digital Moisture MeterVerified PurchaseSuper product. It is actually worth when you see it perform accurately and reliably. Sound and light indications for medium and high moisture levels. It is value for money if measuring moisture is critical in your application
- Mukuka MubangaReviewed in the United Kingdom on April 6, 2022
5.0 out of 5 stars Simple and easy to use
Pattern Name: Digital Moisture MeterVerified PurchaseEasy to use with timber
- MAIReviewed in the United Arab Emirates on April 7, 2025
1.0 out of 5 stars Bad product
Pattern Name: Digital Moisture MeterVerified PurchaseThe item was received in bad condition. It’s clear that the wrapping had been opened before it was sent to me. It appears as though someone used it and then rewrapped it—poorly.
-
VossiReviewed in Germany on December 30, 2013
4.0 out of 5 stars Funktion super Beschreibung miess
Pattern Name: Digital Moisture MeterVerified PurchaseDie Funktion ist einfach und gut ablesbar, doch eine Beschreibung ohne deutsch ist schlecht zu gebrauchen.
Das gesamte Ergebnis ist aber gut.
- FreakinoldguyReviewed in Canada on March 27, 2018
5.0 out of 5 stars Well worth the money
Pattern Name: Digital Moisture MeterVerified PurchaseThis tool saved me a ton of money. I had a flood and when the restoration company assured me that it hadn't gone under the subfloor in the kitchen I got suspicious. So, I bought this item and took a reading. Well it showed excessive moisture under the subfloor. Then I called the company and told them what the moisture reading was they immediately sent another estimator who confirmed my suspicions. Besides as a bonus once the project manager found out I had a moisture meter there was no more of the "it should be dry" excuses because I'd go with him and take my own readings. LOL.
Living on the wet coast this is a great tool for any homeowner and I've used it pretty much everywhere in my home including the attic. It may not be perfectly accurate but it's definitely accurate enough to let you know if you have problems so they don't become major issues. So I'd definitely recommend this tool for anyone who wants a cheap effective way to check moisture in building materials and burnable wood.