Top positive review
On walls which are to its liking it works very well, but on other apparently similar walls it finds nothing
2 April 2018
An experienced joiner I know well told me he's never found a stud detector that works, and he's never met a tradesman who uses one. However we need to fit some grab bars to the walls in tiled bathrooms, so need to work out where the studs are, either to fix the grab bars to them or specifically to avoid them when using snaptoggles. For about 50 pounds it seemed like this i520 was worth a punt, and one of the cheaper multiscanners on offer from Zircon (which according to their website are the most likely to be able to work through tiles). I find the range of scanners on offer from Zircon confusing and pointless. As far as I can see they all detect studs to 19mm depth, or 38mm in "deep scan" mode (so why wouldn't you always use that mode?) and they all have metal detection and wiring modes. I emailed Zircon to ask which scanner would be best to find studs behind tiled walls and they never bothered to reply so maybe that's a warning that their customer service is going to be useless if you ever have a problem.
Anyway, what I find is that this i520 works very reliably behind one tiled wall and not at all behind another. By which I mean that in wall A I can sweep left and right at various heights in the wall and it signals a stud at the same L-R position each time. To my mind that's a reliable indication that there's a stud there. However in wall B it didn't indicate any studs, even though I can see the plasterboard joins above the tiling. I suppose that means that the scanner works through some tile types and not through others, which may be down to the tile thickness or type (porcelain or ceramic).
However, it still seems useful that on most tiled walls the i520 did repeatedly indicate a stud at a particular location. On walls where it didn't find a stud at least it didn't sometimes spuriously indicate a stud, which is what I've been told most scanners do.