Take it from us, we're experts, we know sharks. We also know shark feeding events commonly known as "shark attacks" and there's nothing on this planet short of prayer that will "Repel a Shark Attack."
Sharks are wonderful predators with a simply fantastic suite of senses designed to confirm when or not a shark should make an attempt at feeding. If these triggers are set, either by mistake, poor visibility, or by predatory design there's nothing some rare earth magnets can do to save you.
Did you read that Shark Shocker guys?
This video is one of the best examples of bald faced shark hucksterism we have had the misfortune of seeing in a long while and a complete disservice to the swimming public at large: