The coupler (1) has a plug part (4) lockable against loosening via a bolting device (12). The bolting device comprises of a radial pre-resting recess (14) and a complete resting stage (18) of one of a housing part (2) and the plug part (4). The stage is di...

Adapter kit (1) has remainder cross section (AR) of the opening, which is dimensioned such that the air mass (mLuft) executes an absorbed oscillation in the connecting pipe (6) by the occurring of excitor frequency in the range from greater than zero to te...