Instruments and apparatus; for physical or chemical analysis (e.g. polarimeters, spectrometers), for measuring or checking viscosity, porosity, etc, for measuring quantities of heat, sound or light

902710 Instruments and apparatus; gas or smoke analysis apparatus, for physical or chemical analysis 902720 Chromatographs and electrophoresis instruments 902730 Spectrometers, spectrophotometers and spectrographs; using optical radiations (UV, visible, IR) 902750 Instruments and apparatus; using optical radiations (UV, visible, IR), (other than spectrometers, spectrophotometers and spectrographs) 902781 Instruments and apparatus; for physical or chemical analysis, for measuring or checking viscosity, porosity, expansion, surface tension or quantities of heat, sound or light, mass spectrometers 902789 Instruments and apparatus; for physical or chemical analysis, for measuring or checking viscosity, porosity, expansion, surface tension or quantities of heat, sound or light, exposure meters 902790 Microtomes and parts and accessories thereof