A beverage filter cartridge comprises an outer container with an access opening. This part, including the rubber band, is completely magnetic. A second MOS transistor is connected in series with the first MOS transistor. Another method includes the step of causing a variation in temperature gradient in the fluid while the fluid flows in the wellbore. The assembly of the lamination stack and housing is then removed from the mold. During extrusion, the support and the rolls rotate so as to shape the extruded cable.