17 Rubber, gutta-percha, gum, mica and goods made from these materials in the form of blocks, plates, bars, foils, cords or bands (all as semi-manufactures) and not included in other classes; plastics in extruded form for use in manufacture; packing, stopping and insulating materials; flexible pipes, not of metal; Rubber, gutta-percha, mica and goods made from these materials in the form of blocks, plates, bars, foils, cords or bands (all as semi-manufactures) and not included in other classes; plastics in extruded form for use in manufacture; packing, stopping and insulating materials; flexible pipes, not of metal