Kevlar and carbon fiber... that's all I know about these. I've been told they generate insane drive. I get the feeling they might work in a stand up board. Check all the curves in these things- definitely not an off the rack type of fin... And that's all I know!
Future Fins: Propeller fin... crazy.
You got me.
I have it on good information that they work really well. I handled them and I can tell you they are insanely light and I believe each one is hand made. Good luck getting a pair.