All products supplied by COF Europe Premier polysteel are coated with 3 mm PVC which aWarranty guarantee is given by 20 years. The advantages are: Because the whole with PVC is enclosed, it can not rust and have insects such as Wasps no possibility to go in this nest. In addition, bacteria and fungi no possibility to attach what many go to maintenance. Also Sun, salt and sea do not affect the products of Premier Poly steel by the application of 3 mm PVC coating on high-grade steel. All products are tested and are not harmful to people and the environment. They meet the standards like this inside the EU. In short, the products of Premier Poly steel are durable and maintenance free!