After I Blindist equal to 3 cable had pierced whose position you also could by slightly cooler consideration and simple tapping the wall can suspect I have gained this locating device because you can not always be 100% secure just in the old building, which the previous tenant or previous owner has to lines as laid and for me every ceiling lamp assembly is a bit Roulette. The unit is well on the way out from the Professional Series from Bosch with a present good value for money, idiot-proof (important to me) and very easy to use. Manual is simple, but understandable. Signal both on the display, as well as the marker ring and acoustically. Below are power lines, metal or wood in the wall with a detection depth sufficient for normal home use in drilling depths. Something disadvantage is the size of the device, if more needs in the corners, but in connection with some consideration should not go wrong.