When a 14-year-old gunman appeared at a Georgia high school Wednesday, officials say they were alerted almost immediately.

That's because of a system called Centegix, which calls and alerts law enforcement once a button is pressed on an ID. Barrow County Sheriff Jud Smith said all of the area's teachers carry the system with their ID.

One teacher at Apalachee High School says the system helped put the school on lockdown even before the shooter opened fire.

"We knew before anything truly even happened before lives were taken, so it's insane the technology that we have access to," teacher Stephen Kreyenbuhl said.

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Centegix says there are more than 600,000 of its badges in use in 12,000 locations. The company says the system makes schools safer by allowing any staff member to trigger a total lockdown just by repeatedly pressing the school alert badge on their ID.

This system is part of a growing market for school safety technology, from cameras and surveillance to artificial intelligence systems designed to detect weapons. It's a more than $3 billion industry that some school safety experts say can sometimes give parents, teachers and students a false sense of security.

"We have what we call shiny object syndrome," said Ken Trump, president of National School Safety and Security Services. "We want to make sure that we're not just creating an emotional security blanket where people feel safer, but doing things that actually make them safer."

Trump says school officials tell him they are often overwhelmed by sales pitches regarding this type of technology.

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"The school security hardware and technology industry is growing rapidly," he said. "It's backed by private equity, oftentimes without research backing, but fueled by lobbyists. And it's about the bottom line: making money."

Trump points out that police were already at the school Wednesday and says technology is ultimately not a substitute for humans.

"When security works, it's because of people. When it fails, it's because of people," he said. "We know that the first and best line of defense is a well-trained, highly alert staff and student body."

Seven states now require their schools to have silent panic alarms, including New Jersey, Florida, New York, Texas, Tennessee, Utah and Oklahoma. That's mandated under Alyssa's Law, which is named after 14-year-old Alyssa Alhadeff. She was killed during the Parkland, Florida, school shooting.