Pro-Arte Composite Silver wound clear nylon Classical Strings. These Strings are made with a unique combination of materials never before used in any musical intrument string. The first and second strings consist of conventional nylon, the other four strings make use of a new compound polymer in place of the nylon. The true breakthrough in this set is in the application of this polmer technology to the many fine strands that make up the cores of the wound strings. In test after test with professional and touring classical guitarists, the composite covered strings have outlasted normal nylon core strings by a factor of 2 or 3 times!