INSTRUMENTS AND DEVICES FOR COMPARING, CONTROLLING, MEASURING, MONITORING, OBSERVING, REGULATING, SUPERVISING, AND TESTING TEMPERATURES, PRESSURES, FLOW THROUGHPUT, AND FLOW RATES;, namely, PRESSURE AND TEMPERATURE [ CALIBRATORS, ] CONTROLS, INDICATORS, GAUGES, [ RECORDERS, REGULATORS, ] SENSORS, SWITCHES, [ TIMERS AND ] VALVES, FLOW THROUGHPUT GAUGES, [ GAS ANALYZERS, GAS MONITORS, GAS SENSORS, GAS DETECTION INSTRUMENTS, ] [ GAS METERS, LIQUID LEVEL GAUGES, ] [ ORIFICE PLATES, ORIFICE FITTIN...