Composite Core Classical Guitar Strings EJ45C Pro-Arte’ Composite strings offer the traditional elegance of our Pro-Arte’ line, with the added benefit of an elevated bass response. The exclusive composite core bass strings in the set produce a bold, projecting low-end, providing a more influential tone than nylon basses. Paired with the mellow warmth of our clear nylon trebles, Pro-Arte’ Composite strings offer a sound which is both alluring and commanding. This Normal Tension set is our best-selling tension, preferred for its balance of rich tone, comfortable feel, and dynamic projection.