The unique construction of SoundLag 4542C means it acts as both a noise barrier as well as a noise absorber, thereby providing dual benefits. Its highly dense and flexible mass layer provides excellent sound reduction properties, whilst its decoupling layer breaks the vibration path between the substrate and the mass barrier, thus allowing the mass barrier external wrap to remain flexible to optimise performance. The external foil facing offers a fire resistant covering and an excellent surface to join adjacent sheets using Foil Tape.