I found the stated range of error to be ambiguous. It was stated as being within 3% of the reading. But the units of measure of the reading are themselves in percent.So I wrote the following to the manufacturer, asking if I had a reading of, say, 10% did that mean the range of error was 9.97 - 10.03% or 7 - 13%.This was their reply:The accuracy is ±(3% + 3 digits) as stated in the manual. To use your example, if the meter reads 10% then it is really between 7%-13%. The website will be updated accordingly. Thank you for bringing this to our attention and if there is anything else you have questions about, please feel free to contact us.

General ToolsMmd4E Digital Moisture Meter, Water Leak Detector, Moisture Tester, Pin Type, Backlit Lcd Display With Audible And Visual High-Medium-Low Moisture Content Alerts, Grays

General ToolsMmd4E Digital Moisture Meter, Water Leak Detector, Moisture Tester, Pin Type, Backlit Lcd Display With Audible And Visual High-Medium-Low Moisture Content Alerts, Grays

Q: Can I use this product to rule out a plumbing leak under my concrete bathroom floor. The outer bathroom wall is concrete & paint is bubbling.

It won't show thru the cement unless it is wet. Also is the wall an exterior wall & you could be getting moisture there. With the paint bubbling you do have a water problem from some where inside or out, but you could check with the tool on the inside in the wall real low next to the cement. It worked real well for my particular problem without tearing up the carpet to find my problem. Hope this helps.

Q: I have a wooden floor that is swelling little bit. I know I had a small water leak. Can this tool help me to check if there is moisture underneath?

ABSOLUTELY! This is just what you need, it tells you the exact moisture where the contacts touch the wood. There is a small button on the face right under the word GENERAL that allows you to pick wood or concrete. I use it on our Maple flooring in the summer to see where we are with water content.

Q: Will it measure moisture in drywall?

Yes. It has two features (1) Wood which I use on dry wall, wood, plastered walls, carpeting.. (2) Building material which I use on concrete floors, concrete blocks... I have found it works well on concrete and I can trace moisture in our basement floors which has helped to target where work needs to be done in outside grading. By the way I am a 78 year old woman and have had "fun" using this meter. Money well spent.

Product ID: 253296938

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Details

Colour
Gray
Brand
General Tools
Product dimensions
24.1W x 3.6H
Battery description
Alkaline
Lower temperature rating
32 Degrees

📏0.3" backlit LCD digits for clear readings

📡Audible & visual alerts for moisture levels

🔩8mm stainless steel pins for precise penetration

Frequently Bought Together

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

Klein Tools ET140 Pinless Moisture Meter for Non-Destructive Moisture Detection in Drywall, Wood, and Masonry; Detects up to 3/4-Inch Below Surface

General Tools PIN3 Replacement Pins for MMD4E, RHMG650 and RHMG700DL Silver

Description

🔍 Stay ahead of leaks and mold—because your space deserves precision protection!

ALL INCLUSIVE KIT - Includes extra pins, protective calibration cap, and 9V battery for immediate use.
MULTI LEVEL ALERTS - Audible and visual high-medium-low alerts keep you informed on the spot.
PRECISION PIN TYPE SENSOR - Stainless steel pins ensure accurate readings in wood, drywall, and concrete.
INSTANT MOLD RISK DETECTION - Quickly identify moisture levels to prevent costly mold remediation.
USER FRIENDLY BACKLIT DISPLAY - Large 0.3" digits with backlight for effortless reading in any lighting.

The General Tools MMD4E Digital Moisture Meter is a professional-grade pin-type tester designed to detect moisture content in wood, drywall, and concrete with a broad measurement range. Featuring a backlit LCD with large digits and audible/visual alerts, it enables quick, accurate readings to prevent mold and water damage. The kit includes extra stainless steel pins, a protective calibration cap, and a 9V battery, making it ready for immediate, reliable use in both amateur and professional settings.

Specifications

Manufacturer	General Tools
Part number	MMD4E
Item Weight	113 g
Product Dimensions	14.1 x 24.13 x 3.56 cm; 113 g
Batteries	1 Product Specific batteries required. (included)
Item model number	MMD4E
Size	Pin Type
Color	Gray
Style	Digital Pin Type, Visual & Audible Alerts
Material	Wood
Pattern	Digital Moisture Meter
Shape	Drywall
Power source type	Battery Powered
Voltage	9 Volts
Item Package Quantity	1
Measurement System	Metric
Plug Profile	Tabletop
Specific uses	Inside; Amateur, Inside; Professional
Included components	Moisture meter, batteries, extra pins
Batteries Included?	Yes
Batteries Required?	Yes
tech_spec_battery_description_toys	Alkaline