I use this device as part of the preparation for the renovation of the electrical system of my home. I spot the current locations of electrical pipes. I also find it with this detector, rebar beams of the slab (to avoid drilling in the beams). As stated in the manual, you have to go several times to the same place, the moment or the detector finds something, and it refines with good accuracy the position of ferrous materials or electrical lines. I used to brick walls (5 cm thick), and for the concrete slab from below for rebar beams, (above the concrete thickness does not allow detect scrap).