Sales of armored backpacks have spiked in recent days following Friday’s Sandy Hook Elementary School shooting, in which 20 children were killed in Newtown, Conn.

The armored backpacks, which feature child-friendly designs such as a Disney princess or Avengers characters, go for as much as $300, according to news reports.

One store selling armored backpacks is Amendment II in Salt Lake City. Co-owner Derek Williams told the Associated Press that the protective gear is in high demand after 20-year-old Adam Lanza killed 20 schoolchildren and six adults at Sandy Hook in what was one of the worst mass school shootings in the country’s history.

"The incident last week highlights the need to protect our children," Williams told the Associated Press. "We didn't get in this business to do this. But the fact is that our armor can help children just as it can help soldiers."

Diagrams show how the armored backpacks should be used, with a child using the accessory as a shield.

Backpackshield.com is another popular destination for armored backpacks in the aftermath of the Newtown shooting. Kerry Clark, the company’s president, said he sold 15 backpacks on Wednesday. Most months, the company only sells one protective backpack.

"It's the busiest I've seen it in my life," he told the AP.

Clark stressed to CBS News that the product does not come with a guarantee that it will save your child’s like.

"Just like a seatbelt increases your odds of surviving in a car crash, these increase your odds of surviving being shot," he told the network.

As sales swell in the wake of the Sandy Hook shooting, some experts believe armored backpacks are a knee-jerk reaction in helping to protect children.

Anne Marie Albano, director of psychiatry at the Columbia University Clinic for Anxiety and Related Disorders, told the AP that the backpacks don’t send the right message. Albano suggested instead that parents should display a calm demeanor, not an anxious one.

"This is not serving to keep children safe," she told the wire service. "This is serving to increase their fear and their suspicion of their peers."

But some parents didn’t question their purchase following the Sandy Hook tragedy.

"It's a no brainer. My son's life is invaluable," Denver resident Ken Larson, who started his school supply shopping early for his 1-year-old son, told the AP. "If I can get him a backpack for $200 that makes him safer, I don't even have to think about that."

There are other companies selling products that protect children, including portable armor that can be inserted into an ordinary backpack.

That product, sold at Amendment II, sells for $199, or $100 cheaper than an armored backpack, Mother Jones reported.

"With kids, you never know when they're gonna take something out of their backpack and not put it back in,” Williams told the publication about why parents would opt for the insert instead of the backpack.