I prone, wing, and downwind foil as well as teach foiling professionally for Real.
I 100 % recommend this leash. It can be such a pain to have a leash tangle around a foil or tangle on itself, and Kaohi's double coil design certainly helps decrease this problem dramatically. For wingers, having two leashes flying around while trying to balance can be annoying, and it is nice how well this leash stays out of your way.
I like the 8mm thickness if you are riding waves as this will help the leash last longer and not stretch out. The Rail Saver handle is really nice as it allows you a safe place to control your board and really nice in the white water.
Nice work guys!