A device having a base part (1) and a removable member (3) that is mounted in removable manner on the base part (1), the base part (1) and the removable member (3) including a magnetic means (15, 35) that generates axial magnetic attraction between them that is at its maximum in an assembled rest position. The device further includes a mover means (4), distinct from the removable member (3), for moving the removable member (3) axially away from the base part (1), starting from the assembled rest position, by turning an actuator member (7) that forms part of the mover means (4), so as to reduce the magnetic attraction between the base part (1) and the removable member (3), and thus facilitate the removal of the removable member (3).