Today, there are numerous types of modern Berber carpet made from a wide variety of materials, Nylon, Olefin fibre and wool are the most frequently used materials. Tunisian Berber carpets and rugs, usually called "Mergoum", which still preserve techniques inherited from ancestral weaving methods. Tunisian authorities are still controlling every piece to guarantee quality and that 'Berber' spirit in designs, patterns and symbols knotted so only wool is permitted with a total ban of any synthetic material, then each rug or carpet is sealed with a red wax sign (of Tunisian handicrafts authorities).