Motherboards; Antennas for wireless communications apparatus; Audio transmitter units; Audio- and video-receivers; Digital multimeters; Distribution amplifiers for audio and video signals; Electronic circuit board; Electronic circuits; Electronic components, namely, piezoelectric switches; Electronic semi-conductors; Frequency meters; Loudspeakers, headphones, microphones and CD players; Oscillographs; Portable radios; Power amplifiers; Radio-frequency antennas; Radio-frequency transmitters; ...