They are made by adding chemical additives which increase its inertness. These are very durable by its tendency of work. They are easily bended and have a capability to work for a long time Features: Excellent finish High durability Fine-finish Sturdy construction Seamless performance Tensile and flexible Corrosion resistant Leak proof Immunity to electrolytic or galvanic corrosion No fungal or biological growth Less wear resistance Nominal rates Dimensionally accurate Reliability Quality assured Easy to install