Pressure measuring apparatus; pressure gauges; pressure sensors; pressure transmitters; pressure indicators; pressure recorders; pressure switches, not being parts of machines, being pressure switches for monitoring and controlling the pressure of gases or liquids, namely, pressure controllers for controlling the pressure of liquid and gaseous substances in industrial processes and pressure indicators sold as a unit; pressure switches and sensors for monitoring, controlling, and switching hydraulic or pneumatic systems; combination pressure switch and gauge comprised of pressure gauges and pressure switches for monitoring, controlling, and switching hydraulic or pneumatic systems, sold as a unit; pressure snubbers for dampening variations in fluid pressure measurements in the nature of devices for protecting pressure instruments against pneumatic fluctuations, surges, spikes and fluid hammer all in the nature of pressure controllers for controlling the pressure of liquid, semi-liquid, and gaseous substances in industrial processes; pressure transducers and transmitters that convert hydraulic or pneumatic pressure into analog electrical signals for monitoring and controlling hydraulic or pneumatic systems; air filter gauges in the nature of air quality measurement apparatus, namely, pressure and flow air filter switches all in the nature of flow switches for monitoring and controlling the flow of gases; air flow balancing instruments, namely, air hoods for balancing air flow in HVAC systems in the nature of measuring and control devices for air conditioning technology, not being parts of HVAC units; averaging air flow grids, namely, air flow sensors for measuring air flow in the nature of measuring devices for air conditioning technology, not being parts of air-conditioning installations; air flow indicators in the nature of pressure indicators; air flow alarms in the nature of alarm installations and alarms not being parts of machines, namely, alarm installations and alarms not being parts of machines; air flow switches in the nature of flow switches for monitoring and controlling the flow of gases; air quality measurement apparatus, namely, particle counters; air velocity meters, namely, flow meters; air velocity indicators, namely, pressure indicators; air velocity switches, namely, flow switches for monitoring and controlling the flow of gases and liquids; manometers; pitot tubes; alarm sensors; anemometers; sound alarms; electrical annunciators; aspirator bulbs for providing a pressure source and for taking air samples in the nature of air analysis apparatus; averaging flow sensors being pressure sensors; bar graph meters, namely, display devices for displaying measurement of physical parameters, in particular, pressure, flow, temperature for use in the field of environmental parameters, all in the nature of digital signage; level indicators; water leak detectors; level switches; level transmitters; timer boards; panel meters and indicators; process alarm switch modules; signal conditioning modules; relays; current transformers and switches; solid state relay monitors; motion and safety switches; particulate transmitters; particulate sensors; timers, counters, and tachometers; vibration and detection monitors; power supplies and transformers; process controllers for monitoring and control of temperature and process; signal converters; static pressures sensors; fume hood monitors; temperature and humidity switches; temperature and humidity transmitters; occupancy sensors; flow sensors; carbon monoxide and carbon dioxide transmitters; air velocity transmitters; smoke detectors; indoor air quality transmitters; thermocouple thermometers; temperature transmitters; temperature sensors and indicators; temperature switches; software for programming and communicating with temperature controllers; mass flowmeters and controllers; flow indicators, controllers, and transmitters; flow sensors; flow switches; pressure gauges; pressure monitors and displays; position indicators; position switches; position transmitters; pressure to current transducers; volume boosters; electric valve actuators; thermo-anemometers; signal generators; multimeters; pressure calibrators; gas leak detectors; liquid conductivity and PH testers; tachometers; sound meters and calibrators; HVAC balancing instruments; ultrasonic thickness gauges; data loggers; gas analyzers; IIOT and wireless transmitters, sensors, actuators, gateways, receivers, interfaces, smart probes; torque sensors; balances and scales; load cells, force gauges; strain gauges; strain meters; data acquisition modules and recorders; gauss meters; hardness testers; light meters; speed sensors; thermal imagers; chlorine analyzers; viscosity meters; rain and snow gauges; water quality controllers and sensors; electrical connectors, panels, terminal blocks, lugs, clamps, and boots; thermocouple connectors.