Review on Stud Finder Wall Scanner - 4 in 1 Electric Wood Detector: LCD Display, Center Finding & Sound Warning – Black by Kyle Mack

I only used it for spikes. I find the readings a bit confusing when looking for an edge. The center mark seems accurate, but the edge mark is not. Edge marks sometimes extend to a quarter of an inch, but usually around the 8th inch. The bolt appears to be 2 inches thick when in fact it is 1.5 inches. I use the following to accurately measure a 1.5 inch pencil 1) measure from left to right 2) move to the right and keep moving even though the arrow and edge band appear. Stop and mark the wall when the border strip disappears. 3) keep moving and mark the center. 4) Measure from left to right 5) Find the right edge using the steps from 2.6) Check the center. 8th is smaller. I usually don't care about the edge, so I mark the center from each direction and drill, nail, or screw between those marks. Note: The center marking is also a little useful. This I usually find less than 8 inches. Also, sometimes reading the same end of a hairpin can give inconsistent readings. Even with the above I will not be returning. This works well enough for my needs and the AC cord warning already saved me. You can even trace the wire for horizontal or vertical runs. In general. I will recommend it as read errors can be caused by imperfect bolts, drywall screws or something else.