A device for administering a fluid product, such as an industrial or a medical compound. The device includes a reservoir (18) in which a plunger (15) is axially movable, and an axially movable rod (16) on which a ferromagnetic rod connector (12) is attached. The ferromagnetic rod connector (12) is adapted for sliding cooperation within the reservoir (18). And, a detachable mechanical connection is provided between the plunger (15) and the ferromagnetic rod connector (12). A ferromagnetic plunger connector (13) is attached to the plunger and a magnet (11), arranged for magnetic cooperation with the ferromagnetic connectors (12, 13), to provide a mechanical connection between the ferromagnetic connectors.
