D-string with a core of new synthetic fibre and chromesteel wound. In the year 1998 the Obligato strings from the Pirastro company set the basis for the developing of a totally new string generation. Initially designed only for violin, the Obligato strings are available also for cello since the year 2000. They possess a warm and brilliant sound and offer a big soloistic and powerful volume. An optimal reaction and the easiest response make them suitable for all ranges. They get immediately playable and offer the highest degree of modulation. Advantageous for these new synthetic strings compared to gut strings is the longer durability and the resistance against temperature and humidity changes. They get quickly tuned.