The perils of buying a used computer - yes, I am too cheap or just not rich enough to buy a new Mac Pro - is that sometimes you find that you inherited "interesting" fixes.
Like this SSD mount:
Yes, that's electrical tape and no, I don't agree with this special mounting method. At least they did put some electrical tape between the case of the SSD and the case of the DVD drive.
I guess this is one way of saving $20, which is what the correct 2.5" SSD mounting frame for a recent-ish (2009/2010) Mac Pro costs: