A bayonet attachment on a cartridge for attaching a mixer or accessory to a multiple component cartridge is formed as a ring-shaped bayonet socket with two internal recesses and two diametrically opposed cutouts forming one bayonet coupling part, whereas the bayonet attachment of the mixer or accessory comprises two bayonet lugs corresponding to the cutouts. In a preferred embodiment, the respective inlets of the mixer housing or the outlets of the cartridge have different sizes or shapes to provide coded alignment between the cartridge and the mixer.