General Tools 4-in-1 Pin/Pad Moisture Meter with Humidity and Temperature Display-MMH800 - The Home Depot

General Tools

Model # MMH800

Internet # 203079383

4-in-1 Pin/Pad Moisture Meter with Humidity and Temperature Display

General Tools 4-in-1 Pin/Pad Moisture Meter with Humidity and Temperature Display

This item has been discontinued.
The Home Depot no longer carries this specific product.

$97.00 / each


Model # MMH800

Internet # 203079383

Since 1910, General Tools has grown to become the recognized industry leader for specialty hand tools and instruments. The MMH800 is ideal for locating water leaks and measuring the moisture content of drywall, plastered walls, floors and subfloors. It includes a pin-type resistance-based sensor and a non-marring (pad) inductive sensor.

  • Two dedicated readouts: Moisture percentage, and ambient temperature plus relative humidity (RH)
  • Measurement ranges: 5 to 50% moisture (wood); 1.5 to 33% moisture (building materials)
  • Moisture measurement accuracy / resolution: ±3% / 0.1%
  • Temperature measurement range / accuracy: 32° to 140°F / ±5.4°F
  • RH range / accuracy: 25 to 95% / ±5% below 75%RH; ±10% above 75%
  • High/medium/low audible indication of moisture level
  • Holds moisture level readings
  • Auto diagnostic check
  • Auto power off
  • Includes two pairs of extra pins (10mm and 15mm long), custom hard carrying case, user’s manual and 1-year limited warranty

Info & Guides

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Assembled Depth (in.)  1.5 in  Assembled Height (in.)  6.63 in 
Assembled Width (in.)  2.17 in  Product Depth (in.)  1.5 
Product Height (in.)  6.63  Product Width (in.)  2.17 
Electrical Product Type  Electrical Tool Accessory  Product Weight (lb.)  0.16 lb 
Returnable  90-Day 
Warranty / Certifications
Manufacturer Warranty  90 Days 


Rated 5 out of 5 by 3 reviewers.
Rated 5 out of 5 by Very easy to use This meter is very simple to use. Switch on, push onto the material, and read the moisture content! Could not be easier. There is also an audio signal for low/medium/high moisture ranges and the ability to lock a reading for hard to reach areas. I obtained readings from 5% to 19% around the house and some seasoned firewood I bought. The current humidity and temperature is also displayed. There are two modes of measuring, using the sharp pins or a pair of flat sensors on the back which are to be pressed onto the material being measured. One can measure the humidity of either wood or masonry materials. There is a good protective cap to keep the sharp probes from getting damaged and injuring the user. The case it comes in is mostly marketing. It is made to look like some expensive instrument case but in reality the inside is just a cheap plastic insert and the box is mostly empty. It would make a nice lunch box! September 4, 2014
Rated 5 out of 5 by This tool saved me thousands of $ I was doing a home inspection on a house i put a contract on and and my inspector buddy let me borrow this because he said i couldnt do an accurate inspection with out it. I was amazed when i started scanning the stucco and some areas in the basement and found high moisture levels. Upon further inspection i could check temperature on the windows showing that the windows were poorly insulated. This tool was the perfect tool for the job so that is why iam writing this review and will purchase with the money i saved from not buying the house that would have been a money pit. September 3, 2014
Rated 5 out of 5 by Helpful Evaluation Tool This is the most useful tool to evaluate any home. I used it to ensure that our bathroom which previous had a leak, is no longer leaking. You can either use the needles on the top to poke into wood, or slide the meter along the floor for a reading. When I was testing the basement it was hard to see the screen and the meter chirps warnings when the moisture level is medium or high, which is helpful. You can also lock the screen after a reading and then look at the number later. Overall I highly recommend this, it can save you lots of money by proactively looking for water related problems. September 8, 2014
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