For some time now, a couple of years in fact, I have been looking for brackets like these, not constantly but slipped into my mind a few times. Problem is most modern ATX cases still have the 3 or 4 5.25" drive bays from the days where users could have 2xCDROM/RW and 1xDVDROM/RW in those days the space was necessary, the hard drives always get dropped to the bottom of the case. I am guessing nowadays, like myself, many home users only have 1 5.25" drive bay occupied with a DVDRAM which does everything but we still have 3 or 4 unoccupied bays and hard drives sitting on the bottom. Problem for me especially with the large graphic cards now available is that there is a mess of cables and very little space to fit more than 1 hard drive around a long graphic card. This is the solution, its simple and works brilliantly. Take out hard drive(s) screw bracket to hard drive(s) and pop them in a 5.25" drive bay. There are no instructions and several ways to fix the brackets just choose which suits you best.
Now my 2 hard drives sit under my DVDRAM in 2 of the 4 5.25" bays I have available and a bonus is I can and have reversed my hard drives so the power and data cables face the front thus hiding any wiring and saving even more space. My XFX Radeon HD5870 graphic card has lots of room now, more air flows around it and there are no hard drives to obstruct it. I can even install a 2nd graphic card now the hard drives have been moved without juggling drives around.
Innovative product, cheap and brilliant.