A process for the manufacture of oxalic acid dihydrate in which an aqueous solution of sodium oxalate is contacted with hydrochloric acid and the resulting mixture then cooled to precipitate oxalic acid, followed by optional recovery and recycling of the sodium oxalate and hydrochloric acid into the reaction chamber. 125, comprising an afocal zoom lens. Another method is described for scaling a waveform in which the available accuracy and resolution is manipulated for a given waveform. The hose comprising the thermoplastic elastomer of the invention can be readily molded and recycled, is excellent in heat resistance, water resistance and mechanical characteristic, and has a low specific gravity. When installing an electric fixture or device, information specific to that device is punch holed, written, engraved or etched onto the information template previously recorded onto the surface of the marking plate.