A sanitary insertion unit which has a sealing ring (1) with a sleeve-shaped extension (2), the free end region of which extension (2) has a head (3) which protrudes circumferentially and, when the extension (2) is inserted into an associated line section, can be deformed at least in regions in such a manner that the head (3) of the extension (2) is placed onto the inner circumferential wall of the line section (5). The invention also relates to a sanitary insertion unit which has a flow regulator or is designed as a flow regulator, the outer circumference of the housing of which flow regulator bears a clamping edge region for, in particular, sealing and clamping the flow regulator between two interconnected line sections, wherein the flow regulator bears a sleeve-shaped extension, the circumferentially protruding head of which, produced from elastic material, can be deformed, when the extension is inserted into a line section, in such a manner that the head is placed onto the inner circumferential wall of the line section. Finally, the present invention is also concerned with a shower fitting having a line section which is configured in the form of a shower connection and in the line interior of which one of the above-described insertion units can be inserted.