Recommended filters for environmental analysis and controlling both air and water pollution. Made of 100 % borosilicate glass fibres with binders. Extremely low content in alkali-earth metals. Chemical stability: It keeps all its properties in contact with acid solutions (except hydrofluoric acid) and basic solutions at moderate concentrations. Measurement of dust release in workplace and production processes and the purification of compartment air. Stable up to 180 °C for GF 10. High flow speed and high permeability to air. Suitable as filter belt measuring instruments and automats for air filtration and analysis. Separation of soot; oil mist and suspended particles. Filtration time acc. to Gurley.