The bulletproof panels are designed to withstand multiple rounds from a handgun — and two of this season’s bestsellers are emblazoned with Disney princesses and Avengers superheroes.

“Here’s our demographic: parents with kids,” said Steve Naremore, founder of TuffyPacks, a Houston-based company that sells bulletproof backpack inserts. “It’s a real morbid niche.”

And a growing one: Sales have increased every year since 2016.

This is America in 2019, where mass shootings have become so commonplace that consumers are buying bulletproof backpacks, clipboards, even three-ring binder inserts, that they hope will protect them from gunfire. Retailers across the country say they have seen growing demand for bullet-resistant products for children — as well as for doctors, teachers, flight attendants and taxi drivers — giving rise to an industry of ballistic goods for everyday Americans, though there is little evidence the products are actually effective.

For the first time, Office Max and Office Depot have included bulletproof backpacks among their back-to-school offerings, while online retailers are marketing bulletproof whiteboards, chair cushions and kids’ puffer vests that tap into a growing sense of fear and helplessness.

“So many of the things we’re investing in today, whether it’s smart-home technology or protective backpacks, are about safety and security,” said Marshal Cohen, chief retail analyst for the market research firm NPD Group. “Every time we have one of these incidents, it’s a reminder of how just how vulnerable we are.”

As a result, bulletproof products have become a booming business that picks up every time a large-scale shooting rattles the nation. This month, gunmen in El Paso and Dayton, Ohio, killed at least 31 people and injured dozens more with military-style rifles.

Within hours, Leatherback Gear, which sells backpacks that convert into bulletproof vests, saw a 12-fold increase in sales. “It was all hands on deck all weekend,” said Brad de Geus, who founded the company with his brother three years ago. “Everybody’s fielding calls and emails.”

The company’s backpacks — named simply “civilian one” and “tactical one” — were designed by active-duty law enforcement officers and sell for $330 to $400. Demand has been so high, de Geus said, that the Costa Mesa, California, company is in the process of releasing two new styles, including a sporty model for $280 and a smaller-sized children’s bag for $100.

“It’s just like having a fire extinguisher or using a seat belt,” he said. “These are personal devices for life-threatening situations. It’s as simple as that.”

Academics who study mass shootings say there is little, if any, proof that bullet-resistant products make children safer. Instead, they say, schools and lawmakers should focus on preventing gun violence by banning assault-style weapons and high-capacity magazines.

“This is pure marketing to exploit fear,” said Matthew Mayer, a professor at Rutgers University whose research focuses on school violence prevention. “We have no evidence that these things work. They’re giving kids and their parents a false sense of security.”

Mass shootings, he added, “are fluid, rapidly developing, unpredictable events.” The chances that a child would have such a backpack handy at precisely the right moment — and quickly calibrate the shooter’s position and the bullets’ potential trajectory to position backpack — is “something so beyond reality that it’s just not logical.”

Even so, demand for such products continues to grow. Though analysts do not have hard numbers yet, they estimate the market for bulletproof consumer gear is in the tens of millions of dollars. School security, meanwhile, has ballooned into a $2.7 billion-a-year business.