NERF - which stands for Non-Expanding Recreational Foam - was first introduced as the "world's first official indoor ball." It was marketed with the messaging "Throw it indoors; you can't damage lamps or break windows. You can't hurt babies or old people." By the year's end, millions of NERF balls had been sold.
Today, NERF is best known as a variety of foam-based weaponry, with other Nerf products including balls for sports such as football, basketball, and baseball. Their best known toys are their dart guns (referred to by Hasbro as "blasters") that shoot ammunition made from "Nerf foam", which is partially reticulated polyether type polyurethane foam.