These material have
primary efficiency (for dust particle>1-5um)
medium efficiency(for 1-5um dust particles)
high efficiency(for dust particles <1-5um)
Primary efficiency material are mainly used for regular dust-collection protection of big oxy generator and air compressor as well as primary filtration of air conditioning systems of the industrial sectors like the electronics, chemicals, pharmaceuticals and ***** efficiency materials are usually used in ordinary industries and public areas, while the applications of high efficiency can be found in dust-free, purifying shops in the optoelectronics, LCD manufacturing, biomedicine, precision insutrument, foodstuff&beverage and PCB industries