19 Building materials (non-metallic), in particular cover plates, lining panels; non-metallic, prefabricated ceiling parts and components for cellers, including using reinforcing iron; basins of concrete for plants; mortar; non-metallic chimney cowls and parts therefor, in particular covering hoods; chimney systems, chimney shafts and elements not of metal, ceramic, plastic or natural building materials, namely, bricks, fireclay and similar material, including all the aforesaid goods of a combination of metal and mainly not of metal; chimney cowls and closures (non-metallic); rigid pipes for building, not of metal or of metallic and mainly non-metallic materials combined; prefabricated chimney components, not of metal; extension stones, lids and spark filters, all the aforesaid goods included in this class