This an extension for a VR stand (in Germany sold as PIRANHA, in Asia from TopAce, and in other countries with other brands), which allows to put both Oculus Touch controllers on the stand. You need to print two Oculus Touch Cradles by ClassicGOD as well, which you can screw to the extension. One of them you have to print out flipped horizontally. I used a normal screw 3x12mm to fix them to the middle-piece.
BTW, I also cut the stirrup so that the Oculus Rift glasses fits on it.