Needle felts produced from polyester fibre perhaps constitute almost 75% of the total filter bag usages. Polyester as a material is very versatile & so adapts itself to a wide variety of filtering applications, from aluminum smelters, steel making, cement, and a variety of other use ages. With dry heat, polyester filter bags can generally withstand until 150 d C operating temperatures with short peaks of a few degrees above this. However, with element of moisture in the dust/gas, polyester fibres tend to disintegrate by the phenomenon of "hydrolysis". A wide variety of fibre thicknesses offer themselves to needle felt manufacturing. Our unique back-process allows us to produce highly efficient needle felts from "microfibres".