The ISO-KF connection was developed by Leybold and is now the main flange type used for small fittings (up to 50 mm inner diameter) across the world in any vacuum application.
It permits rapid fitting and replacement of components in vacuum systems via its quick release clamps, hence its alternate name, the QF, Quick Flange.
Every connection consists of two symmetrical ISO-KF flanges, a cantering ring with O-ring gasket, and a clamping ring. High vacuum tight ISO-KF connections can be made without the use of tools simply by turning the wing nut of the clamping ring.
It is typically suitable for pressures down to 10-7 mbar/torr, able to withstand pressures of up to 5 bar, and can be baked up to 200 °C when metal seals are used, or 150 °C when FPM gaskets are used.
The main feature though is the speed of assembly, with no tools needed to provide a vacuum tight seal.