Ytong autoclaved aerated concrete (AAC) is a brand of the century:Now,one of the strongest brands in the building materials market,that has long been a guarantee for the best thermal insulation and solid quality,also numbers among the premium group of top German products.At the same time it represents the culmination of an unparalleled period of development.In 1929 the first aerated concrete was produced in the Swedish town of "Yxhults Snghärdade Gasbetong",gave birth a little later to the world's first registered trademark for abuilding material,Ytong,which went on to change the construction industry for good. The rapidly growing acceptance of the material is closely linked with the introduction of the Ytong building block in 1960.this newly developed large format block offered unheard of dimensional accuracy at the time and could be used to construct an almost seamless wall using thin bed mortar.It permanently and fundamentally changed the traditional masonry trchniques.The Ytong blocks have been sold wrapped in yellow llastic film since 1967.This yellow film is part of the marketing strategy that places the emphasis firmly upon brand recognition.