Electric, electronic and optical apparatus and instruments in the field of high-frequency and optical engineering, namely, attenuators, terminations, calibration kits for calibrating high-frequency electric test instruments and composed of high-frequency open circuits, high-frequency short circuits, high-frequency broadband loads, air lines, and attenuators, verification kits for verifying that a network analyzer is operating within a specified performance and composed of attenuators, air lines, a variable impedance, and verification disks, calibration substrates, test fixtures, electric connectors, fiber-optic connectors, coaxial cables, twin lead cables, optical cables, waveguides for propagating microwave electromagnetic energy, high-frequency voltmeters, high-frequency ammeters, high-frequency watt meters, high-frequency frequency meters, high-frequency phase meters, hybrid couplers for electromagnetic waves, electron tube amplifiers, semiconductor amplifiers, high-frequency electron tubes, transistors, oscillators, absorbers of radiofrequency electromagnetic energy, reflectors of radiofrequency electromagnetic energy, windows for radiofrequency electromagnetic energy, oscilloscopes, transmitters of radiofrequency electromagnetic waves, receivers of radiofrequency electromagnetic waves, high-frequency electric and electronic couplers; electric and electronic switches and circuits; electric and electronic connecting elements, namely, plug-type electric connectors, coaxial cables, twin lead cables; apparatus for recording, transmitting or reproducing sound and/or images, namely, audiotape recorders, videotape recorders, radio, television and satellite transmitters; blank magnetic data carriers; data processors and computers; magnetic data carriers with computer programs for electronic data processing and data carriers with computer programs for electronic data processing and educational computer programs for technology instruction