Electrical and electronic apparatus, instruments, components and accessories, including resistors, potentiometers, hysteresis motors, capacitors, lightning arrestors, surge arrestors, antennas, electrical chokes, transformers, electrical indicators, coils, attenuators, electrical and electronic networks involving both active and passive circuit elements for use in electronic equipment, electrical cables, printed circuit boards, amplifiers, direct and alternating electrical supply units for primary use in testing of electonic equipment, electric and electronic attachments for player pianos and organs, control knobs for electrical equipment, and delay lines,