ISO 8434-3:2005 specifies the general and dimensional requirements for the design and performance of O-ring face seal connectors made of steel for tube outside diameters or hose inside diameters of 6 mm through 38 mm, inclusive. These connectors are for use in fluid power and general applications where elastomeric seals can be used to prevent fluid leakage, including leakage caused by variations in assembly procedures. They are intended for the connection of tubes and hose fittings to ports in accordance with ISO 6149-1. Both metric and inch tubing can be accommodated by changing the sleeve. In the past, these connectors have been used predominantly with inch tubing. For new and future designs, the use of metric tubing is preferred.

ISO 8434-3:2005 also specifies a performance and qualification test for O-ring face seal connectors.