5 stars because there's nothing wrong with them (aside from the hardware but that's to be expected). These are functional and reasonably attractive. Why the oblong perforations? Well, think about it: you can't hang the mirror until the brackets are screwed to the wall, but once the brackets are screwed to the wall, the mirror won't fit between them. The answer is to screw the bottom retainers tight to the wall at the top of their slots (those carry all the weight), but stop just just shy of that with the top and side retainers so they can be slid upward and outward until the mirror is positioned, then slid back to hold it vertical. Their job is to keep it from tipping forward, which is an important job but doesn't take much strength.So, that''s what I did, and it worked well. Precise measuring and drilling is necessary, using level and plumb bob. Of course I replaced the included wood screws with longer, stronger pan heads screwed into wood studs (which takes another tool, a studfinder), but the result is secure. Wood screws fastening sheet metal without countersinks is sloppy work, and the included plastic drywall anchors are perhaps the flimsiest I've ever encountered. Fortunately, I have a large collection of screws so finding just the right size was feasible.5 stars, because nothing's wrong with them, but how do they compare with alternatives? Clear plastic mirror retainers screw directly to the wall, which means the screw heads are visible and there's no gap behind the mirror. These stainless steel retainers are stronger and sleeker, but more expensive (not unreasonably expensive, but the plastic ones are practically free), and they're far trickier to install correctly. Having used both, I can testify that clear plastic retainers, or simple offset stainless retainers, are perfectly adequate. Yes, the plastic ones are acrylic and acrylic degrades over time, but I've never seen one break. Some in my house I installed 50 years ago look exactly the same as when they were new. Furthermore, anyone can screw them to any wall sufficiently accurately. The bottom ones are installed, the mirror placed in them, held in position while one at the top is screwed in; after that, they can all be installed with the mirror in place. Screwed into wood is still best, but since you can use as many as you like, positioning them where you like, even only into drywall is enough. Since they're all screwed tight to the wall surface, they're actually incredibly strong against both shear and lateral forces.I'm not trying to talk you out of buying these. I'm just saying that the common, ordinary alternatives in this case are also worthy choices with some distinct advantages.Incidentally, pay attention to the width of the gap into which your mirror (or whatever) has to fit. These hidden-hardware brackets are cushioned (mostly to keep the screwheads away from the mirror's silvering) but most are not (and needn't be). You want a gap a little larger than the depth of your glass, but not much larger.

Great mounts. I got these to mount a plexiglass panel over an old window. A little snug hold on 0.25", but did fit without bending. Feels durable, minimal profile. Works great!