Abstract: A plug for light wave conductors or photo-conductors with a plug housing into a rear end of which a photo-conductor bundle with at least two photo-conductor fibers is introduced, and from an oppositely lying front end of which there emerge ferrules, into which, in each case, one of the photo-conductor fibers is introduced. The ferrules are supported in a ferrule housing which is installed in a plug housing correspondingly formed for the reception of the ferrule housing. The ferrules are movable, spring-loaded in their axial direction, in which the plug is intended for being plugged together with a coupling housing that receives this plug. The ferrule housing comprises a core housing and a core interior housing, which are designed for the reception of two ferrules. The ferrules are supported in the core housing. Front ends of the ferrules extend forward through the core housing and rear ends of the ferrules extend into the core interior housing.