Summary

Newer flight controllers like the Naze32 and CC3D are 36 mm wide with a 30,5 mm hole pattern, while older ones are 50 mm wide with a 45 mm hole pattern.

This adapter makes it possible to mount a 36 mm board on top of a 50 mm power distribution board.

I also have another variant available that makes it possible to mount LED strips directly in front of and behind the flight controller:
http://www.thingiverse.com/thing:683999