I use one, just a big magnet on a watch band. Does it work? I'm not sure, no problems yet. Think I paid 79 dollars for it 2021, see they are now 129.oo Wow..
Impressive video on utube with floating dummy with fish tied to arms and legs. There seem to be more and more shark bites world wide. 100% effective? Who knows? Wearing one or two Sharkbanz may relieve the worry about an unpleasant encounter though.