Thomastik-Infeld Spirocore cello strings have the high-performance capacity, quick response, and great projection. Their brilliant durability makes them become one of the most popular cell strings in the world. Unlike common steel strings, Spirocore's performance is able to give professional musicians more stable and clear intonation. They are are known for their clarity and focus. Their powerful round sound and beautiful timbre represent the world-class quality cello strings.