Optical, electrotechnical, electronic, and mechanical equipment, instruments and apparatus all for use in testing and measuring the performance and efficiency of filters and filter media; function, capacity and exhaust gas test stands and testing equipment for testing and measuring the efficiency and fractional filtration efficiency of filters, namely grain size analyzers, filter testing apparatus, optical aerosol spectrometers, optical particle counters, dry dispersion apparatus, particle charge analyzers for air, gases and aerosols, aerosol generators, dilution systems, aerosol spectrometers, environmental chambers, and test piece mounting apparatus; vibrating, conveying, sifting, compressing and separating apparatus test chambers for conducting tests under different environmental conditions; apparatus for recording, compiling and evaluating data from test machines and apparatus; safety devices, diagnosis apparatus and installations constructed therefrom; monitoring apparatus and installations constructed therefrom for status-oriented machine monitoring, control and regulating; electric and electronic computers for controlling and regulating the aforesaid goods and peripheral devices therefor, namely printers, test desks and remote control apparatus, programs recorded on data carriers for controlling and regulating the aforesaid goods; parts and fittings for all the aforesaid goods

Engineering; Engineering design services; Engineering services, namely construction, calibration, scientific and industrial research for planning of installations in the field of aerosol measurement and particle technology, conducting surveys in the field of aerosol measurement and particle technology, computer programming services in the field of recording, processing, evaluating and storing measurements, and engineering services for controlling and regulating machines and installations, consulting services in the field of aerosol measurement and particle technology