Looks like the same stuff on the body as well, it looks like the new colored stuff from sollarpaddles, it is a kevlar/carbin fiber weave with many different color combos!!! looks great on those fins.
After I got the hang of working with it, I got a power sander. That stuff's a bugger to sand. Much easier to keep coating it to get it smooth. A comlete second coat of epoxy is a waste as far as strength and is rather expensive, but the alternative for me was many coats of urethane.
You can seal the fuzzies on the edges of the fins with fast epoxy and a very thin applicator. Lay down a line on the edges, push the fuzzies in, let it dry and lay another line on top.
OTOH, if you use sleeve on the fins you can eliminate at least one, usually two fuzzy edges by pulling the sleeve against the edges first.
Good golly Miss Molly....that thing is bulletproof....LITERALLY...
The carbon fiber/red Kevlar looks too cool. I thought about using some of that in blue on my upscale Praetor, but I didn't trust myself with it. It's too expensive of a cloth to screw up. Looks like you got the hang of it.
So what motor are you going to fly this creation on?