9 ELECTRONIC EQUIPMENT FOR USE IN CONNECTION WITH THE REPRODUCTION OF AUDIO SIGNALS-NAMELY, PHASE SHIFTERS, ECHO UNITS, CHANNEL SELECTOR SWITCHES, FLANGERS, MOUTH TUBES, DISTORTION UNITS, FREQUENCY EQUALIZERS, GUITAR SUSTAINERS, PREAMPLIFIERS, AMPLIFIERS, WAH-WAH PEDALS, OCTAVE SYNTHESIZERS, NOISE ELIMINATORS, ENVELOPE FOLLOWERS, MIXERS, BASS BOOSTERS, FOOT PEDALS, TREBLE BOOSTERS, ATTACK CONTROLS, ATTACK EQUALIZERS AND CABLES