Recently I made (well, didn't make) a takeoff on a heavy wave. The wave was not even head high but had a lot of power on a shallow bank. One of my quad fins went through my calf muscle to the bone. 

I should have stuck to my single fins lol.

Anyway, I've since put those proteck fins in that board. They're hard plastic with a soft rubbery edge. They perform well enough for me. 

Thought I'd post this as a reminder to remember to take the edge off sharp fins, beware of your fins when falling, and consider safer fins as an option.