19 Sand, gravel, crushed building stone, asphalt, bitumen, cement, gypsum tiles, plaster, concrete, marble blocks for construction; building materials in the nature of concrete, gypsum tiles, clay flooring, potters' clay, building stone, marble, preserved wood for building, construction, road construction purposes; non-metallic transportable buildings; poles not of metal for power lines; crash barriers not of metal; natural and synthetic asphalt roof coatings in the form of panels and sheets, being building materials; bitumen cardboard coatings for roofing; bitumen coating for roofing; doors and window frames of wood; traffic signs not of metal, non-luminous and non-mechanical, for roads; monuments and statuettes of stone, concrete and marble; building glass; prefabricated swimming pools not of metal; aquarium sand