Coded couplings (distinctive quick couplings) of nominal width 5 have a coloured sliding sleeve made of aluminium, which facilitates the assignment of the right plug, which is marked with the same colour. The distinctiveness is achieved through a shape coding of the coupling plug and the coupling (octagon, circle, hexagon or triangle). Warning: Coded coupling plugs as a rule also fit in uncoded coupling sockets! The plug profile is compatible to the coupling plugs Parker-Rectus series 21, Parker-Rectus series 90, Camozzi, EWO, KANI, Festo model series KD3/KS3, IMI-Norgren series 233, Aventics series CP1-NW 5.