SAN DIEGO (NEWS 8) – Mass shootings at schools across the country have claimed the lives of dozens of students over the past few years.

In response several companies have created bulletproof backpacks designed to help keep kids safe.

The bulletproof backpacks range from $200 to $400. They are designed with high strength material Kevlar which can withstand gunfire.

Lynn Westover, a veteran and firearms expert, recently put the backpacks to the test.

He shot at one from 21 feet away using three different weapons: A Sig Sauer .380 caliber handgun, a Sig Sauer .45 semi-automatic and a Smith & Wesson M&P 15T, .223 caliber rifle.

The Smith & Wesson M&P 15T, .223 caliber rifle, commonly referred to as the AR-15, was a similar weapon used during the mass shootings in Newtown, Las Vegas, Aurora, San Bernardino and most recently in Parkland, Florida.

In the test, the backpacks held up against the handguns but not the assault rifle.

Makers of the backpacks have been up front about what their products can and can’t protect against.

The bottom line, Kevlar is considered to be lighter but to stop the bullets from an assault rifle, backpacks would need an extremely heavy military grade plate. It just wouldn't be practical for kids to carry around the heavy grade armor.

Brad Degeus, co-founder of Leatherback Gear says, “They're very heavy, they're very cumbersome and they're not worn all the time. They're not designed to be worn all the time.”

Leatherback Gear makes backpacks that can turn into vests (highlighted in a previous News 8 story).

According to Degeus, when deployed as a vest, their product will not stop an AR-15, but a recent test showed in its backpack form, with two Kevlar plates, it could.

Additionally, any books or laptop could add as an extra level of protection.

“You're essentially getting the protection that law enforcement gets every single day. Hopefully you'll never need it, but it’s there if you do,” he said.

Rick Carlson, a retired San Diego police officer, told News 8, “it should not give you a false sense of security, but at least it’s some security.”

Further, Carlson said the backpacks may not be for everyone. He suggests parents educate their child about what to look out for and how to get away from a potentially dangerous situation.

“If you can help yourself in any way, shape or form, either get out, defend yourself or stop the person that's attacking,” he said.

There is clearly a market for protective gear as the companies that make the backpack told News 8 that every time there is a shooting, their sales skyrocket – some products even sell out.