A method and apparatus for equalizing digital data signals is disclosed. The first is a cloth outer shell like the kind used on the outsides of many types of luggage bags. The other end is suspended by a magnetic field between a magnet affixed to a support and another magnet affixed to the other end. The user could further adjust the angle to meet the demands of various situations. The invention also provides a gas alarm unit constructed by connecting the above pump device to a portable gas alarm device provided with a specific gas feed adapter through a connecting tube. This invention is an insert-molded article obtained by inserting a functional resin film in a mold beforehand and injecting a polycarbonate resin to mold it, wherein the polycarbonate resin comprises a constituent unit derived from a dihydroxy compound represented by the following formula.