Electric measuring devices, namely, for leak detection, filling state measures and filling state switches, namely, radar filling state measures, [ capacitive filling state measures ] and filling state switches, ultrasonic filling state measures, [ vibration filling state switches, ] flow meters, in particular magnetic-inductive flow meters, ultrasonic flow meters, eddy frequency flow meters, mass flow meters, suspended solid particle flow meters, [ calorimetric flowmeters, ] nuclear magnetic flowmeters, pressure measuring apparatus, temperature gauges, for measuring substance concentration and ph values, [ apparatus for analyzing gases, ] sludge level meters, optical apparatus and instruments, in particular spectroscopic measuring instruments, in particular for detection of a characteristic of light such as transmission, scattering, fluorescence or refraction, mass spectrometers; diagnostic apparatus, not for medical purposes, in particular for leak detection; filling state measures and filling state switches, namely, radar filling state measures, [ capacitive filling state measures ] and filling state switches, ultrasonic filling state measures, vibration filling state switches; flow meters, in particular magnetic-inductive flow meters, ultrasonic flow meters, eddy frequency flow meters, mass flow meters, suspended solid particle flow meters, calorimetric flowmeters, nuclear magnetic flowmeters; pressure measuring apparatus; temperature gauges; analysis apparatus, not for medical purposes, in particular for measuring substance concentration and ph values; [ apparatus for analyzing gases; ] sludge level meters; optical apparatus and instruments, in particular spectroscopic measuring instruments, in particular for detection of a characteristic of light such as transmission, scattering, fluorescence or refraction; mass spectrometers