Transcript for New device touted as preventing shark attacks

With the warmer weather upon us, we're already seeing swimmers and surfers attacked by sharks. A new device plans to prevent attacks, but not everyone is convinced it works. Here's Marci Gonzalez. Reporter: Tonight, shark warnings on both coasts, putting beachgoers on alert and looking to new technology to stay safe. You're paddleboarding next to approximately 15 great white sharks. Reporter: That alarming scene this month in Orange county, California. And in Florida, at least five attacks already this season. My best friend was attacked by one. Reporter: Looking for a solution, lifelong surfer Nathan garrison partnered with scientists to create sharkbanz. It's designed to be there to give you some defense, instead of just relying on luck. Reporter: In this video, sharks immediately attack a dummy leg filled with bait. Once the device is attached, sharks quickly swim away. The predatory shark species have the most powerful electrical senses. Reporter: Garrison claims the $80 cuff creates an electromagnetic field around you, disrupting the shark's senses. Zack Davis was wearing one in January when a black-tip shark bit him. It let go after two or three seconds. Garrison calls the attack highly unusual, and believes the shark let go quickly because of the device. Some experts disagree. Unfortunately, a lot of people treat these shark repellents like a Superman's cloak. The reality of it is, there are no 100% proven shark repellents. Reporter: With or without the technology, experts recommend avoiding the ocean at dawn or dusk. That's when sharks typically feed.

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