A method and apparatus for switching a data packet between a source and destination in a network. The first and second structures are defined by lithography processes using photomasks. Light permeable resin 4 is filled in the reflecting case so that the interior of the reflecting case 3 and the one ends of the plurality of leads are fixed. Thus, the only power consumed by the TWT amplifier is that associated with the cathode heater and the electronic power conditioner used as the electron beam source. The ligature and the mouthpiece are structured to define several discrete positions that can be selected by a musician. The caddy holds the cartridges oriented in opposite directions to minimize interference by the spare cartridge with using the caulking gun.