(Bay News 9/CNN) When you plan your day at the beach -- the only things on your mind are the sand and the water.
But if you're like Chad Campbell and plan to dive a little bit deeper -- great white sharks may also be on your mind.
"They might come in but just close enough to where you could see them then go away and stay on the outer perimeter of us," Campbell says.
That's because of a device called a "Shark Shield."
For the first time ever -- users can buy it from its first U.S. store. And it’s located in the Tampa Bay area.
"You wear this on your ankle and this antenna trails behind you in the water. Inside this antenna we've got two electrodes,” explained Shark Shield General Manager Amanda Wilson.
And those electrodes create an underwater electric field.
When a shark comes close to someone wearing the Shark Shield -- the devices causes spasms and keeps the sharks away.
Officials say what's also interesting about Shark Shield is even though it repels the sharks, it doesn't hurt them."
"It doesn't cause any long-term damage. It just causes the muscular contraction of their snout. As soon as they're outside of the field, that spasm stops," Wilson said.
And that's good news for water lovers like Chad.
He says he and other divers have had far too many close encounters with sharks without the device. But now they feel safer diving to new depths.
"Well it definitely worked and I'm not getting in the water without it anymore for a safety precaution," he said.