PCI-E Riser Flat Mount for external cards

Designed this so that I could attach PCI-E riser card externally to my PC. Not sure if the spacing on all PCI-e risers is the same but in my experience they are all clones of each other.

There are some recesses in the underside to hold square m3 nuts.

I just used these with some double sided sticky tape to stop them topping over.