Here we have a surfboard fin used on not only Greg Noll Da Cats or Stemwinders but other models as well. This is not an original but it is a recreation or copy of an original. It is made of molded plastic as the originals were and will duplicate all the imperfections of the original fin used in the molding process. I have a few left there will not be anymore recreated. I have them in black, white and blue. Free shipping in the USA. Later models had a set screw to secure the fin. I a...lso have the correct stainless steel set screw that will fit in the fin. The fin can be used with or without the screw. The screws ar $5 extra.