Device for quick determination of moisture in buildings, during construction, and more. With the help of the GMI 15, moisture in wood can be detected up to a depth of about 3 cm, as well as in concrete or screed up to a depth of about 4 cm. It even detects moisture behind ceramic tiles and various wall and floor coverings. The measurement is easily performed by placing the device on the surface to be measured, so there is no need to penetrate the measurement object. The display is shown via "Digit" and is relative, meaning that the values can be well compared with known moisture levels. Applications include moisture assessment for real estate agents, property management, homeowners, architects, experts, construction companies, and more.