They work for what I use them for but here are the issues to be aware of when you need precision braces.1. The holes are not countersunk to fit the included screws and no screw will fit. I'll have to countersink them or buy some pan head screws to work with. In fact, the material may be too thin to sink.2. The brackets are not 90 degrees as noted by another reviewer. If I had read the reviews I would not have bought. I figured China could at least make some quality corner mount and I didn't need to read the reviews. Also, they were 0.06 inches thick, and the spec sheet says 0.05 inches thick. I'm glad they are thicker. I think they make them from scrap or defective materials due to the difference in thickness, and another reviewer commented that the second batch he bought was different from the first.