ELECTRICAL OR ELECTRONIC COMPONENTS MOUNTED OR HOUSED IN ORDER TO FACILITATE THEIR USE FOR INSTRUCTIONAL OR INSTRUMENTATION PURPOSES; NAMELY, AMPLIFIERS, OSCILLOSCOPES, CATHODE RAY TUBES, ELECTRONIC DIGITAL READOUTS, OSCILLATORS, SIGNAL DECODERS, ELECTRONIC INTERFACES, MICROCOMPUTER INTERFACES, ELECTRONIC CONVERTERS, PHOTOELECTRIC CELLS, RADIO RECEIVERS, ELECTRICAL POWER SUPPLIES, TIMERS, LASERS, FIBER OPTIC CABLES, FIBER OPTIC COMMUNICATION BOARDS, GEIGER TELLERS, RATER METERS, GEIGER MULLER TUBES, GEIGER MULLER TUBE HOLDERS, GEIGER MULLER SCREENED LEADS, GEIGER MULLER TUBE POWER SUPPLIES, DIGITAL SCALER-TIMERS, SOLID STATE DETECTORS, GEIGER TELLER CARRYING CASES, LIGHT METERS, PH METERS, OXYGEN MEASURERS, TEMPERATURE MEASURERS, CONDUCTIVITY MEASURERS, SOUND MEASURERS, GEOPHYSICS MODULES, ELECTRODES AND TRANSDUCERS FOR GEOPHYSICAL SURVEYING, INCLUDING SPONTANEOUS POTENTIALS, EQUIPOTENTIAL PLOTTING, RESISTIVITY SURVEYING, REFRACTION SEISMOLOGY, PROTON MAGNETOMETRY AND RADIOACTIVITY, VIBRATION GENERATORS AND PARTS AND FITTINGS THEREFOR, STROBOSCOPES, MICROWAVE TRANSMITTERS AND STANDS THEREFOR, MICROWAVE RECEIVERS AND STANDS THEREFOR, MICROWAVE PROBE RECEIVERS, POLARIZATION GRILLS, MICROWAVE REFLECTORS, BRAGG SCATTERING LENSES AND TURNTABLES, MICROWAVE REFRACTION PRISMS, LENSES AND BLOCKS, MICROWAVE WAVE GUIDES, FRESNEL ZONE PLATES, ULTRASONIC TRANSMITTERS, RECEIVERS, TRANSDUCERS, PLATES, REFLECTORS, MAGNETIC FIELD MEASURERS, COMPUTER PROGRAMS, PHOTOETCHERS FOR ETCHING GROOVES OR TRACKS TO FORM ELECTRICALLY CONDUCTIVE PATHWAYS ON BOARDS, FLUID VELOCITY METERS, CHROMATOGRAPHS, BIOLOGICAL AMPLIFIER FOR MONITORING ELECTRONICAL ACTIVITY ASSOCIATED WITH THE HEART OR OTHER MUSCLES BY AN AUDIBLE SIGNAL OR IN CONNECTION WITH AN OSCILLOSCOPE, TECHNOLOGY TEACHING EQUIPMENT ESPECIALLY ADAPTED FOR THE EDUCATIONAL ENVIRONMENT; NAMELY, HIGH VISIBILITY DIALS AND FAILSAFE BIOLOGICAL AMPLIFIERS, ELECTRICAL OR ELECTRONIC COMPONENTS FOR INSTRUCTIONAL AND INSTRUMENTATION PURPOSES NOT SO HOUSED; NAMELY, CAPACITORS INDUCTANCES, TRANSFORMERS, RESISTERS, SOLID STATE ELECTRONIC APPARATUS, SWITCHES, COMPUTERS, THYRATRONS, VACUUM TUBES, COMPONENT ENCLOSURES, PLUGS, SOCKETS, CONNECTING LEADS, BATTERIES, METERS, OPTICALS, CABLES, GAS FILLED TUBES, LOUD SPEAKERS, MICROPHONES, ELECTRONIC METERS ANTENNAE, THERMONIC VALVES, COMPUTER-AIDED DESIGN PROGRAMS, ENVIRONMENTAL KITS CONSISTING OF PRIMARILY ELECTRONIC UNITS FOR THE MEASUREMENT OF ENVIRONMENTAL QUANTITIES AND LEVELS COVERING LIGHT, TEMPERATURE, OXYGEN, PH, CONDUCTIVITY, SOUND, AND RADIOACTIVITY, ALL FOR USE IN LABORATORIES IN TEACHING AND EDUCATIONAL PURPOSES