Turnbuckle

This thing is more about printable threads than a turnbuckle.

Print without support, it's all in the geometry!

In a nutshell : M10 printed male and female threads that are printed horizontally for extra strength and better print resolution.

Most printers have better XY resolution than Z so this has the advantage of:

They are not subject to the 45deg rule so true threads can be created which are compatible with their metallic counterparts..
The layer orientation means they are particularly stronger and less prone to layer de-lamination.
Longer length of thread due to more stable print heights.