This is a Tunnel Style Fin for a Liquid Force Ronix Wake Surfing Board.
I have not tried it yet but will be testing it out this weekend.
I tried this fin this weekend, and it broke off at the base on the second run I made. The design produces too much resistance for a wakesurfing fin, but could work in the ocean on a longer board. I would print this one using 100% infill if you plan on trying it.