I have two Behringer hum destroyers (great name of course) and a Behringer Mic100 tube preamp, all of which don't have rackmount capabilities, so I needed a place to put them, and well, it works.
The only other thing to say is that I don't think it could hold a lot of very heavy items as you can definitely press on it and watch it bow a bit, but keep in mind, it is metal, so providing you're not loading it, it should be fine, but your mileage may vary.
I'm not sure what else to say, other than it's a flat 1U tray to place items in a rack mount enclosure. Looking at the tray, the variety of holes makes it pretty versatile too, so I'm definitely happy with it.