Moisture meters are used to measure the percentage of water in a given substance. This information can be used to determine if the material is ready for use, unexpectedly wet or dry, or otherwise in need of further inspection. Wood and paper products are very sensitive to their moisture content. Physical properties are strongly affected by moisture content and high moisture content for a period of time may progressively degrade a material. Meters for wood Newly-cut logs can have a moisture content (MC) of 80% or more, depending on species. Since wood shrinks, and can also split, twist or otherwise change shape as it dries, most wood is dried before being used. This is most often done using a kiln, but may use the air drying method, which is much slower. In most parts of the United States, the minimum moisture content that can be generally obtained in air drying is about 12 to 15 percent. Most air-dried material is usually closer to 20 percent moisture content when used. In-kiln drying is usually monitored by some type of moisture meter. Moisture meters are used to measure the amount of water in the wood so that the woodworker can determine if it is suitable for the intended purpose. Building inspectors and many more, carpenters, hobbyists, and other woodworkers often are required to have moisture meters. Wood flooring installers, for example, have to verify that the MC of the wood matches the relative humidity in the air of the building. If this step is skipped, a vast array of problems may present itself: cracking, cupping, crowning, buckling, sunken joints, and cracked finishes. The problems caused by varying degrees of moisture content in wood go beyond simple shrinkage in the dimensions of wood parts. Problems with distortions in the shape of the wood, such as twisting, warping and cupping, occur because of the difference in the degree of dimensional change in wood cells tangentially (perpendicular to the grain and parallel to the growth rings) versus radially (perpendicular to the growth rings). A moisture meter gives a reading of the approximate moisture content of wood. The reading helps in determining whether the wood is suitably dry for its intended purpose. The moisture content reading can also assist in planning a project design that will accommodate future changes in dimension caused by changes in relative humidity. The amount of overall shrinkage lumber will undergo in