Chatterblock 1250 is a carefully engineered mix of recycled wool and polyester, which is lofted and thermally bonded to produce an efficient user friendly acoustic insulation. Chatterblock 1250 is designed for use in intertenancy walls and floors and works by reducing sound build up within the cavity - thereby increasing the sound barrier properties of the system. Chatterblock 1250 has been classified as having - High Flow Resistivity - as summarised in Gib Intertenancy Sound Control Systems (1994). * Manufactured from Wool/Polyester Chatterblock is clean and safe to use and requires no special safety apparatus.