This device I had put on me, because the basement walls had some minor efflorescence in the base area. After folding down the cap exposed two probe tips, which I then poked directly into the wall joint; is pressed while the large center button. The display was in several places in this fugue different between 0.5 and 0.8% moisture were displayed (from 1% of the measured value is considered questionable). Daily ventilation and putting up a moisture collector (hygroscopic salt) brought Remedy, the moisture in the wall gradually decreases measurably. Moreover, the device can be adjusted, if the moisture is to be measured in timber or in masonry. In addition, at a button again, the LCD display is illuminated, so you can see the display well even in dark corners. One more thing: With the device even Raumttemperatur is measurable! I need the device but not daily but to avoid or finding the cause of humidity in living rooms, basements and garages it meets very good service - all in all: highly recommended!