Summary

This is an adapter for the mayatech 38mm (6mm root) hub (https://bit.ly/2U7jGm4) and Gemfan 9x5 folding props (https://bit.ly/2RGl964).

It is made for a 5mm motor shaft and this single part will stop the blades opening and closing too much as well as reduce the central opening down to a 5mm motor shaft too.

https://www.youtube.com/watch?v=Ta9ORLZyXlI

If you use CURA and need to split it into the separate parts to print then watch this:
https://youtu.be/C6oA6nkGjko

Happy flying!