Multicellular * cross-fluted * plastic blocks used as inserts for air filtering and air cooling apparatus in buildings using natural ventilation being component parts of evaporative air coolers [ and air filters ]

Semi-finished products for use as components in domestic and industrial air-cooling devices, in domestic and industrial ventilating devices, in refrigerating plants, and in cooling towers, namely, evaporative cooling and humidification packing comprised of synthetic filter materials, plastic foils not for packaging purposes, and plastic fibres not for textile purposes