Designed for the Team Blacksheep (TBS) Oblivion frame to allow a 20mm stack with M2 screws to be mounted inside the canopy without the need to drill out the frame.
I use M2 Socket head hex screws 25mm in length inserted into the bottom of the adapter and then screw on a hex spacer on top of it.
The adapter does need to be oriented correctly bolting through the frame so that the grooves in the adapter line up with the design of the frame. This was done to be able to make the plate thick enough to hold up to stress on the stack when crashing.
I printed mine using Flexible PLA as it has a higher shore rating. You can probably use TPU as well, but make sure your infill is high enough that it won't rip apart or squish too much when bolting to the frame.