A Christian school in Florida is selling bulletproof panels for pupils to put in their backpacks.
Florida Christian School, in Miami, lists the “ballistic panel” for parents to purchase on its website at a cost of $120 (£90).
The school’s head of security, George Gulla, said the panels offer another “level of protection” to students “in the event of an active shooter”.
"The teachers are trained to instruct the students to use their backpacks as a shield to protect themselves," he told CNN.
The panels are slim pieces of material that reportedly weigh less than a pound.
More than 200 school shootings have taken place across the US since the infamous Sandy Hook attack in 2012, the LA Times reported.
In that incident, 20-year-old Adam Lanza killed 20 children and six adults in a school in Connecticut.
But school safety consultant Kenneth Trump told NPR he was sceptical of the new panels.
"After every high-profile school shooting, we have an explosion of gadgets, gurus and charlatans," he said.
"Corporations see dollar signs, and believe that schools have huge budgets to buy new products and services."