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

Works great. It showed me that a slab I was getting ready to use wasn’t quite ready and probably saved me a failed project down the line. Easy to use. I’m happy with the purchase.

Very good quality for the price point. Worked well on sheetrock areas

I 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.

Super tool. I like that it tests construction materials as well as wood for our woodstove. Very handy when air drying milled lumber.

Reliable. 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.

As 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.

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.

So, a nice device but some caveats. In order to get the 'factory approved' read you MUST push the pins into the wood "all the way" (yes, about a good 1/3 of an inch) or it simply isn't the devices best read. Now for those who cannot get that full insertion General makes the MMD7NP which does mostly the same thing without pins! Less overall effort. Not an issue into, say, drywall but you will find 'hard firewood' (read, long burning) can be difficult to obtain full insertion (and REMEMBER these comments, instructions are direct from a live factory rep)... suggested testing methods of, as an example, firewood is to split it open so you can measure internal and external (and the internal that I measured on a piece of firewood was about 20% while the skin or bark fully inserted was 7.5%... so big difference and maybe enough to cause the wood to start easy and then die out? As most have commented there is NO included manual, factory notes that is on purpose and suggests obtaining it from their website as a PDF. This is a simple device and there is one page of instructions on the site however for inclusiveness sake the 'other languages' make up many more, perhaps why they stopped printing. Fabricated woods or building materials should be easy to test, soft woods firewood would also be agreeable but 'real hardwood' will be more difficult to pin test or 'rip' and test both internal and outer regions for dryness. The device can withstand some real pressure to "insert" but don't twist or bend while inserting, the results are broken pins and no reading.