A dual purpose coupling piece is provided for on the one hand the screw coupling of a disposable pressure container with a dispensing gun, and which further includes means for on the other hand also cooperating in a bayonet-type coupling with a suitable handheld applicator for application of the compound as in the handheld use. A suitable handheld applicator is also provided. The coupling piece and/or the handheld applicator may be designed for the production as one single product using injection moulding. Further provided is an assembly of a container with the coupling piece, and a process for producing the coupling piece and the assembly, as well as the handheld applicator.