I found out about these things a few days ago and had to have them. As usual, you can't MISS ANYTHING with General Tools. Great device, easy to use and perfect for my needs. We buy LOTS of firewood and now I don't have to worry about being burned (pardon the pun) by vendors who claim to be selling seasoned wood. You simply remove the lid, stick the probes into the wood, press the button and your moisture percentage is there! An easy to read large display and a bargain price compared to others that don't fare any better. Highly recommended.