An optical adddrop filter is formed using a hologram which is tuned to a wavelength in an optical signal. The projections are separated by vent grooves and have top surfaces which form a broken circular circumference around a firing path for a lacquer bullet. Preferred methods of depositing the thermal transducer involve the deposition of the thermal transducer on the smooth surface of a wafer prior to the slicing of individual sliders. The detector for AGC can continuously and effectively detect an output swing of the VGA. The cooling tube is provided with indirect and direct cooling sections and cools the metal vapor transferred from the vessel to produce the metal powder. The radio apparatus is useful for attaching to objects that undergo bending stresses, such as tires.