The Keystone Equipment and Toy Company originated in Boston, MA in 1910. The company began making movie cameras and projectors ten years later. It’s K- series 8mm cameras were made from the late 1940’s through the 1960’s. They were easy to use with it’s “Electric-Eye” meter and simple settings.
The modern look of the 3-lens Capri K-series caught the eye of the props master for AMC’s show Mad Men. In season one, Don Draper films Sally’s birthday party with this camera.
All of Keystone’s products were made in the United States, which was something they were quite proud of and used as a selling point. They were wildly successful after WWII as servicemen settled in suburbs and raised their families. Keystone sold kits including everything needed to film and show home movies.