flange 119 and bayonet noses 130 and projections 131 on bayonet ring 123 is visible the bayonet noses have the usual tightening surfaces that are facing and directed toward the cartridge a limitation of the bayonet action during locking and opening is provided by two stops 132 on two opposed bayonet noses which cooperate with corresponding stop surfaces 133 in the mixer inlet section furthermore bayonet ring 123 is provided in addition to projections 131 which are not sharp edged but beveled with two stop cams 137 having straight edges projections 131 and stop cams 137 cooperate with incisions 121 a that are formed in bayonet tabs 121 of the mixer these incisions have a bevel 138 on one side and a sharp edge 139 on the other side these locking means still allow the mixer to be rotated out of projections 131 after a clockwise rotation by 45 u00b0 i e the mixer can be rotated in the counterclockwise direction by 90 u00b0 but can no longer be turned back as the sharp edges 139 are now abutting to stop cam 137 as already mentioned in fig2 and 25 a respectively the mixer has been placed on the cartridge and snapped in and in the illustration of fig2 the mixer has been.