Kindly Reminder: It should be noted, Before starting calibration, keep the machine from the body and any objects, including metal, wood, or even walls. Identify potential moisture problems up to 40 mm (2 in) the surface. Check for moisture on or the surface of wall, carpets, ceilings, and sub-floors. It can help contractors, woodworkers, and homeowners on wood, drywall, and concrete projects. In addition, the current reading can be recorded via hold function. The MT68 comes with flashlight and moisture indicator allows you to quickly and easily detect surface moisture in darkness materials and locate moisture distribution in the wall, floor or ceiling in a time-saving manner. The MT68 is not only ready to use immediately, it also impresses with fast response times during measurement and displays helpful additional information such as minimum and maximum values on the easy-to-read display with backlight. Finally, the machine can adjust the humidity alarm value according to the your needs, After all you knows the real working environment the most. Specification: Moisture measurement range: 0-100 Measurement error: 2.5% Measured depth 5-40mm(0.2-1.57inch) Auto Power Off Trigger 30 minutes of inactivity Storage Temperature 0~45C Power Source: 3x AAA battery(battery not include) tip: English without battery Material: plastic colour: Black Package Contents: 1 x Wood Moisture Meter 1 x English instructions Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.