List of unwound gut core strings:

• Pirastro Chorda for violin, viola and cello: meant for period (baroque) instruments. They contain a variety of unwound and wound strings. For violin, the E and A string are often combined with other gut core strings such as Pirastro Eudoxa or Pirastro Oliv.

List of wound gut core strings:

• Pirastro Eudoxa for violin, viola and cello: the most popular strings before the inroduction of synthetic core strings. They have a very warm and full sound, but are slightly less responsive than other gut core strings. Mainly suited for older instruments because of their lower tension.
• Pirastro Gold for violin, and cello: cheaper gut core strings, with a warm sound but less volume than other gut core strings. The steel E string is very popular for violin and is usually combined with other (synthetic core) strings.
• Pirastro Oliv for violin, viola and cello: premium gut core strings with a very rich sound that are pretty responsive (considering they're gut core strings, that is). Even now a favourite amongst string players that are looking for a full yet rather powerful sound typical for gut core strings.
• Pirastro Passione for violin, viola and cello: a recently developed line of gut strings. They try to combine the advantages of gut strings (rich, warm and complex sound) with the advantages of synthetic core strings. They stay far better in tune than their gut string brothers, need less break in time and have a longer life span. The sound is slightly less complex than Eudoxa and Oliv strings, but has more projection. For cello, the A and D string are metal strings, and only G and C strings are gut core strings.
• Pirastro Passione Solo voor violin: Solo edition of the Passione strings mentioned above. They have a little bit more volume and are slightly more direct than standard Passione strings. Suitable for instruments that do need that little bit extra tension and projection.