A control serum for a dry process is provided that dose not show misfit in measurement values by the dry process and a wet process. The easy open feature is generally defined by a weakened portion in the bag. The waveform is examined by comparing the operating characteristics during the first movement event with at least one of: the operating characteristics obtained during a previous movement event; an expected value of the operating characteristics; or an expected duration of a moving time period during which the first rail is expected to move from or to an unlocked position. When the backrest moves between the upright and reclined positions, the footrest unit moves relative to the arm frame in concert with the seat.