Salt/Sea water is good to strengthen/thicken skin. Wash your hands multiple times a day with it. Keep a bottle of sea water in the truck.
Sterkte met die eina.
What is the small black "pin" on the "inner side" of the fins? Metal/rubber? Could it have been attached to something? Check for work marks.
Also
Does it apear that there are some sort of control that could go through the shafts holding the fins?
This really looks like a concept for a small...
I frequently work with my planer, router, jigsaw, grinder and even my small Dremel and a have a healthy respect for it.
Good luck with the healing Zog.
If you look at what Bose head phones can do to cutting out sound as well as industrial active sound reduction ear muffs I cannot see why this will not work.
I will follow this thread in the hope that somebody buys one and give feedback on it.