The backpacks cost several hundred dollars each, the New York Daily News reported, with at least one company offering children's styles with motifs like Disney princesses. Companies reported sales have gone up several hundred percent, admittedly from a low base.
Elmar Uy, vice president of BulletBlocker, a Massachusetts company, said he first realized something dramatic had happened because of the increase in customer interest last Friday.
"Part of my daily activity is to monitor the numbers," he told the Daily News. "I was seeing numbers I'd never seen before and I thought it was a glitch. Our Web traffic was10 times more than normal. I turned on the TV and there it was on CNN."
Uy said BulletBlocker backpacks, which cost up to $600 each based on size, will stop more than 99 percent of handgun bullets.
Adam Lanza, 20, who had already killed his mother, gunned down 20 children and six staff members at the Sandy Hook Elementary School last Friday before taking his own life.