Take pinless (non-invasive) Moisture measurements on wood and building materials without damaging the surface with the depth of approx <0.78" (20mm) with Extech's MO257 Moisture Meter. The ball moisture sensor provides smooth gliding on hard or delicate surfaces. Easy-to-operate with automatic calibration of the meter when powered on. Large backlit triple LCD displays moisture reading and Max and Min readings. User can adjust two alarm levels where it will show visual alert with flashing “RISK” or “WET” indicators with beeper alert. Ideal for building restoration projects and applications where moisture detection on floors, tiles and under carpets is critical. A must have tool for analyzing the after-effects of water leakage behind walls and in ceilings and also measuring moisture content on a non-flat surface