The neutral material they're made of (aluminum) and the application of latest-generation liners that reduce the passage of oxygen and other potential oxidants to a few parts per million ensures the product has perfect organoleptic qualities and eliminates the risk of contamination by the material which makes up the cap itself. Characteristics that form the basis of the growing success of such closures, not just on central and north European, American and Asian markets but also in countries with a long wine-making tradition, such as Italy, France and Spain.