Frame for holding the carbonfiber collimator laminate. It's made a bit thicker in all directions to be more durable, it has no problems being used despite this.
The holes for the lights on the insert dont quite line up, but this has no impact on operation.
Fits on an MK4S if cut into 4ths, but i got it printet in one piece in nylon from PCBway.
The author marked this model as their own original creation.