110 is a cartridge-based film format used in still photography. Kodak introduced it in 1972. It is essentially a miniaturised version of Kodak's earlier 126 film format. Each frame is 13 mm × 17 mm (0.51 in × 0.67 in), with one registration hole.
The film is entirely housed in a plastic cartridge, which also registers the image when the film is advanced. In addition, there is continuous backing paper, and the frame number is visible through a window at the cartridge's rear. Thus, the film does not need to be rewound and is very simple to load and unload. The film is usually pre-exposed with frame lines and numbers, a feature intended to make it easier and more efficient for photofinishers to print.
Unlike later competing formats, such as disc and APS film, processed 110 negatives are returned in strips without the original cartridge.