b which is intended to act as a seal between coupling part 7 and seal opening 21 of application component 20 is also designed as a molded on or extruded on sealing element 11 b in the present exemplary embodiment as shown in fig5 molded on sealing element 11 b is formed on second thread section 5 b of coupling part 7 molded on sealing element 11 b in this specific embodiment is molded into a radial recess and is pressed against the inner thread of seal opening 21 when coupling part 7 is screwed in this similarly establishes a seal between coupling part 7 and seal opening 21 it is furthermore conceivable that sealing element 11 b is a coated elastic flat sealing ring which has a rectangular cross section and plastically fits to the thread in a seal forming manner when the coupling part is screwed in and thus in particular also compensates for diameter tolerances of the threaded fitting and forms a seal due to the machining of the threaded fittings large fluctuations in diameter are indeed a matter of course e g even when executed in aluminum in particular a soft or plastic material in the form of a flat seal or extruded or in particular made of a thermoplastic elastomer tpe or a particularly soft silicone may be advantageous here possible radial sealing edges are also not illustrated which are compressed by the mounting action and result in a sealing contact within the bore 6 sealing ring 11 b may furthermore be designed as.