A Marman clamp is a type of heavy-duty band clamp: this allows two flat cylindrical interfaces to be simply clamped together with a ring clamp. Also sometimes known as a "Marman ring".
A common use for Marman clamps is their use as a quick-disconnect connector in wide-diameter fuel lines. Another example is their use in space vehicles, for example on the Cassini Plasma Spectrometer on the Cassini orbiter.
The Marman clamp was invented by Herbert Marx, better known by his stage name of Zeppo Marx as one of the Marx Brothers. It was manufactured by his company Marman Products. At the time it was designed to secure cargo during transport. The U.S. Military used it to transport the atomic bombs used at the end of the Second World War.
Marman clamps are found in almost every modern moving vehicle.