MICROPHONES MADE OF GRAPHITE, CARBON BLACK, SILICON CARBIDE; HIGH VOLTAGE PROTECTORS MADE OF GRAPHITE, CARBON BLACK, SILICON CARBIDE; PILE RESISTORS MADE OF GRAPHITE, CARBON BLACK, SILICON CARBIDE; RING RESISTORS MADE OF GRAPHITE, CARBON BLACK, SILICON CARBIDE; POTENTIOMETERS MADE OF GRAPHITE, CARBON BLACK, SILICON CARBIDE; ROLLS FOR TRANSFORMERS MADE OF GRAPHITE, CARBON BLACK, SILICON CARBIDE; DYNAMO PARTS, NAMELY, ROLL HOLDERS MADE OF GRAPHITE, CARBON BLACK, SILICON CARBIDE; DYNAMO PARTS, N...