A device for mixing a first substance and a second substance, or for transferring at least one of the substances, which are present in a first or second receptacle, the device including a first adapter with a circumferential wall, along which extends a cannula body, and a hollow-cylindrical section that is connected to the cannula body; a second adapter with a circumferential wall, along which extends a cannula body; and a hollow-cylindrical section that is connected to the cannula body; when the first and the second adapter are assembled, the hollow-cylindrical sections inter-engage in a liquid-tight manner, and the first and the second adapter are connected to each other in a detachably screwed manner.