A note about keys: Traditional instruments are normally concert pitch. That means that if you play the note C on a bouzouki, mandolin, fiddle, accordion or anything else, it sounds C just as it would on a piano. It can get confusing with flutes and whistles, which are often available in multiple keys. On these instruments, they are defined by the lowest note played, by covering all six holes. So a D whistle is actually concert pitch, even though classical musicians would say that that instrument is in the key of C. Confused yet? The short version: D whistles & flutes are what you need to play at a session or with other instruments. If you have any questions, contact us and we will get back to you as quickly as we can.