Disclosed are a stator assembly and a torque assembly device. The biological QNFT system includes the following three main elements: an aerosol generation system; an exposure chamber; and an aerosol sampling subsystem. A part of the battery chamber protrudes from the back face of the back cover. The selectable connections may be defined in an integrated circuit mask or may be electronic switches. The rotational speed is also sensed and a speed signal conveyed to the computing means. A rack whose toothing engages with the pinion is mounted so as to be axially displaceable in the steering housing.