A disk recording-and-reproducing device includes a box-like casing and a lid hinged to the casing to rotate about its pivot for opening and closing the casing. An electrolytic solution for a secondary battery according to this exemplary embodiment contains at least an aprotic solvent and two particular compounds. The encoders also include a configurable infinite impulse response digital filter that selectively uses one or more sets of filter coefficients to filter the difference signal andor the sum signals. The second optic is located anteriorly to the first optic and is of a positive power. The first region is removably coupled to the second region. The vitreous tubing is rotated in the laser beam and is moved in the laser beam to provide a taper in the interior bore.