Brackets to mount a 3.5" HDD in the rackmount case for the PC Engines APU board. This is one of two models, there's an actual intended mounting position (but only for a 2.5" drive), thats what this one mounts to, and then there's a mounting position for a second motherboard. The original version fit perfectly but the mounting position meant that on one side the mounting screws interfered with the SATA cables. So I modified it to move the drive backwards 10 mm, increased the thickness of the brackets to raise up the HDD and also made the holes a bit bigger and added material to the HDD mounting tab for increased strength. On the photos v1 is still being used.