240mm

240 millimeters (mm) is a unit of length in the metric system, equal to 0.24 meters or approximately 9.448 inches. It is used to specify dimensions across a range of technical fields and products.

In photography and cinematography, 240 mm can denote the focal length of a telephoto lens, providing a narrow field of view and greater magnification for distant subjects. Lenses of this length are commonly used for sports, wildlife, and distant architectural subjects.

In construction and manufacturing, 240 mm appears as a common dimension for components and finishes. Examples include square tiles measuring 240 by 240 mm, pipe and duct diameters around that scale, and various machine parts where 0.24 meters is a convenient, standard size.

In military history, 240 mm has been used as a designation for large-caliber artillery and naval guns. Calibers of this magnitude were characteristic of early 20th-century coastal defense pieces and some naval guns, reflecting the era’s emphasis on heavy firepower and long-range engagement.

Overall, 240 mm is a versatile dimension that appears in tiles, piping, optics, and historical artillery, illustrating how a single measurement unit spans multiple domains.