Best used as a replacement water ski fin. Might be used on a solid construction old-school paddle board, sometimes called a beaver board. This item might be adapted for use with a kayak, ideally a wooden hull kayak (screws) or glued to a plastic kayak hull with EM89 Adhesive (no screws).

This is a Water Colors brand water ski accessory, made by SportKraft International in Chaska MN.

The fin base is about 7 inches long by 1 3/8 inches wide. The total fin depth is only 1 3/16 inches. Fin comes with 4 screws (not guaranteed to be stainless steel).

One might be inclined to screw such a fin to the bottom of a plastic kayak with Silicone Sealant. In doing so you might create leaks below the water line! Successful and safe use of this fin in this capacity is solely the user's responsibility. It would be recommended to do so only do so if you have not other recourse, the kayak is not worth very much and the kayak will only be paddled close to shore on ponds or small lakes while wearing a Life Vest.