Photos reveal Mark Zuckerberg surfing while wearing an $84 bracelet that claims to fend off sharks

• Mark Zuckerberg was photographed wearing a Sharkbanz bracelet while surfing recently.
• The device is designed to keep sharks at bay by emitting an electromagnetic current, though some experts have expressed doubt about its effectiveness.
• Barack Obama has previously been photographed wearing the device.
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Facebook CEO Mark Zuckerberg was spotted wearing a bracelet designed to protect against shark attacks while surfing on Thursday.

Photos from TMZ show Zuckerberg with a Sharkbanz bracelet on his ankle during an outing with his hydrofoil surfboard in Kauai, Hawaii. A Sharkbanz spokesperson confirmed the Facebook co-founder had bought a Sharkbanz 2 device off the company's website.

Earlier this month, Zuckerberg posted a video on the surfboard. In the video he appears to be wearing the bracelet.

The $84 Sharkbanz bracelet claims it can fend off sharks by emitting an electric current that is designed to keep sharks at bay by interfering with the shark's ability to sense electromagnetic fields when searching for prey.

The device has been touted by several professional surfers, including 1988 World Surf Champion Barton Lynch. Last year, former President Barack Obama was photographed wearing a Sharkbanz bracelet.

Despite its popularity, some experts have been wary of the device in the past. Late scuba diver Erich Ritter, known for filming "Bull Sharks: World's Deadliest Sharks," told the German publication Deutsche Welle (DW) in 2017 that he believes Sharkbanz does not work.

"These Sharkbanz act only as a psychological safeguard," he said. "They have no effect at all."

Chris Lowe, director of the Shark Lab at California State University, Long Beach, told The Inertia, a surfing and outdoors publication, that he has yet to see any data to support the use of products like Sharkbanz. Though, Sharkbanz has provided several videos showing bull sharks avoiding dummies wearing the device. The bracelet has also been verified by third-party research at Coastal Carolina University, according to the company's site.

Ritter said the magnets in the bracelet are nowhere near strong enough to deter a shark. He pointed to an incident in 2016 when a 16-year-old boy was bitten by a shark in Florida while wearing a Sharkbanz bracelet. At the time of the accident, Sharkbanz cofounder Nathan Garrison said the shark attack was an anomaly and explained the device is only able to protect against certain kinds of attacks.

Zuckerberg's hydrofoil surfboard also has a zebra pattern on the bottom which is reportedly designed to deter sharks. In theory, stripes make it difficult for sharks to identify prey.

It was not Zuckerberg's first time on a hydrofoil board. In 2019, the CEO posted another surfing video.