TOPPERFO® Micro can be produced in different perforations. The distance of the 0.5 mm hole in the standard product is 2 mm, but can also be greater or smaller. As variants, the distances determined were 1.8 mm and 3 mm and are now also measured in terms of sound absorption according to the standard ISO 354. The sound absorption of Micro 1.8/1.8/0.5 is exceptionally high with Aw 0.9 for walls and ceilings. The product is classed as an “A-absorber” which corresponds to the best possible classification according to the EN 11654 standard.