The invention relates to a sanitary insertion unit having an insertion housing, which can be inserted into a sanitary supply line and has a continuous flow controller, which has a flow-through port through which a fluid flows, in which flow-through port a restrictor is provided, which is arranged in an installation plane oriented transversely to the flow direction, and delimits a control gap between itself and an adjacent wall that delimits the flow-through port. The insertion unit according to the invention is characterised in that the flow-through port is designed as an elongated hole, the longitudinal extent thereof being arranged transverse to the direction of flow, and in that the restrictor is designed as a web shape or a string shape and is held with its web or string ends on the wall sections that are oriented transversely to the longitudinal extent of the flow-through port in such a manner that the restrictor is orientated in the region of the elongated hole in the longitudinal elongation thereof. Because the flow-through port and the restrictor are elongated and not ring shaped, the insertion unit can be used in combination with a noncircular, particularly elongated, flow-through cross section, without being limited thereto.