"POLYDROS" cellular glass plates are made by the fusion of vitreous powder in which a thermal-chemical process in the glass powder creates cells in a state of partial vacuum and sealed off from each other. Because there is no connection between the cells, "POLYDROS" cellular glass is a material of maximum quality, with hard-to-beat technical features: Because the cells in "POLYDROS" cellular glass are hermetically sealed and unconnected, the product is totally sealed against water vapour and absorbs no humidity. "POLYDROS" cellular glass is an inorganic material, without added resins, and is entirely fireproof (M0). It does not burn or produce toxic gases. It is rigid and non-deformable, and chemically resistant to both organic solvents and most acids. Unlike other insulations, "POLYDROS" cellular glass is highly compression-resistant. Neither bacteria nor fungus survive in "POLYDROS" cellular glass, making it an ideal material for use in areas requiring environments of maximum security against the propagation of such micro-organisms.