Nerf foam is made from a solid, spongy cellular. Polyester resin reacts with a compound while CO2 is simultaneously released by another reaction. It is this gas that creates open pockets within the polyurethane that, in turn, makes the material soft and light.
Parker Brothers originally developed Nerf, beginning with a four-inch (102 mm) polyurethane foam ball. In 1969, Reyn Guyer, a games inventor, came to the company with a volleyball game that was safe for indoor play. After studying the game carefully, Parker Brothers decided to eliminate everything but the foam ball. In 1970, the Nerf ball was introduced as the "world's first official indoor ball". Marketed that one can "Throw it indoors; you can't damage lamps or break windows. You can't hurt babies or old people." The ball filled a strong consumer need and by the year's end more than four million Nerf balls had been sold. The four-inch (102 mm) ball was followed closely by a large version called "Super Nerf Ball". Shortly after, in 1972, a basketball game called "Nerfhoop" and the Nerf football joined the family. The football quickly became the most popular Nerf ball.
The company continued to add to the Nerf line until they handed control to Kenner Products, a sister company, in 1991, when Hasbro acquired the Nerf line through the acquisition of the Tonka Corporation. Over the years, the company has continued to expand the line, adding new looks to existing products. The current line of Nerf products range from various sport balls, blasters with both dart, rocket and ball ammunition, and now onto video game accessories and video games .
Nerf has a wide range of foam balls that are molded to look like various sports balls. They are designed with different color schemes and features, and are less likely to cause damage since they are made from Nerf material.
The company also makes Nerf Blasters, which are toy guns used to shoot ammunition made of the Nerf material in ball, arrow and dart form. Various forms of dart ammunition are available, including a variety tipped with Velcro that can stick to Nerf vests, another tipped with suction cups designed to stick to smooth surfaces, a streamline dart that is used in many Nerf blasters, and a whistler dart that whistles while flying. Nerf is the most popular foam dart blaster brand.
Nerf also produced a new line of "Nerf N-Swords", which are swords that have a nerf material covering a plastic rod in the middle, which holds it together.
Recently Hasbro has released a line of Nerf-branded Super Soakers.