: Some higher-end cameras used a square notch on the top edge of the cartridge to automatically detect the film's ISO speed. Historical Significance and Decline 126 Film & Using 35mm in 126 Cameras

: The film is encased in a plastic cartridge with a paper backing that displays the current frame number through a small window on the back of the camera.

: While the film strip itself is 35mm wide, the images captured are typically 26.5 x 26.5 mm squares .