Printed in 4 parts & epoxied together then sanded smooth. 3D printed in PLA.
It's only slightly in the way while you're trying to write but if you give it a little twist it will come out of the base.
CAD of the fin.
CAD of the center section. I was having trouble getting the slicer to get the brim the way I wanted so I just added the brim to my model.