The Slinky failed as a part for a meter to measure horsepower on World War II-era battleships, but it succeeded immensely as a toy for the baby-boom generation and their descendants. Designed in 1943 by marine engineer Richard T. James, the Slinky began humbly enough when James abandoned his job as an air-conditioner salesman, borrowed $500, and, after slow sales, convinced Gimbel's department store in Philadelphia to grant him space for an in-store demonstration. After the show, the store sold 21,000 Slinkies in three weeks; in the years since its introduction during the 1945 Christmas season, more than 250 million Slinkies have been sold.
Slinky pull-toys appeared in the early 1950s, represented by the most famous Slinky Dog. The firm made many different designs over the years, keeping and updating the most popular examples.