Update: shoulder rest 9 seems to be more sturdy and durable. The clips are a little more encompassing and the base is thinker to prevent bending.
So luke12345's shoulder rest puts the violin in an impossible angle. And I wanted to actually be able to play.
So I created an adapter that lets you attach a normal shoulder rest.
You might need to change the dimensions, depending on your F-F-Fiddle finishing. Mine has several layers of epoxy.