Pirastro Passione Cello StringsPassione C & G cello strings are made from sheep gut core whilst the D & A strings are a steel core string. These can be used together or with other Pirastro string types. Features (C & G): The sheep gut core of the Passione strings is manufactured, wound and polished in the traditional way, by hand. The G string is wound with chrome steel, the C string with tungsten. brilliant sound enormous possibilities with a wide range of sounds surprisingly