In the majority of cases you can use this thing to hold your 2.5" (notebook) hard disk or SSD in place of a 3.5" (desktop) hard disk.
All 6 screw holes are present (and in place) in the plastic, you should be able to screw them in. (These are on the side, there are no holes on the bottom yet.)
Not suitable for server cages as the HDD connectors are slightly displaced from the standard position. Tested and working in an HP desktop, a Fujitsu Siemens and in some Imacs.