Ammeters, high pressure manometers, voltmeters, galvanometers, radon detectors, smoke detectors, carbon monoxide detectors, three-phase current galvanometers, water level indicators, gas meters, thermometers not for medical use, polariscopes, potentiometers, accelerometers, spectrophotometers, photoelectric sensors, diffraction gratings, monochromators, AC potentiometers, double beam spectrophotometers, liquid sensors for detecting presence of liquids, gas detectors for detecting presence of ...