Wood burns best between 15% and 20% moisture content, higher than that produces excess smoke and soot, lower than that burns too quickly. Make sure your fire installation produces safe levels of smoke and soot with this Meter for measuring Firewood Moisture. Just stick this meter into firewood to test its moisture content. Its 4-prong test produces a reading between 3% and 40% moisture content. This meter features a back lit LCD screen with large LCD readout, and includes a 9v battery, padded carry case, and instructions. Includes: 9V battery, padded carry case, and instructions. Features: Stick meter into firewood to test its moisture content. 4-prong test produces a reading between 3% and 40% moisture content. Back lit LCD screen with large LCD readout. Wood burns best between 15% and 20% moisture content, higher than that produces excess smoke and soot, lower than that burns too quickly.