Whats the best open muzzle?

I have used the Freedivers speargun, its simple but works. I had to take the cassette out and sand a lot of the internal plastic pieces and it was much better after that. I like how they incorporated the plasctic sleeve on top of the barrel its a very quiet gun but a little heavy.

I know Daryl Wong uses 3 band muzzles on some of his hybrids, I don't know if he sells them though