This arrangement is for piano and High D tin whistle (the most standard key of whistle that most players have). You could also use a low D whistle. You receive the tin whistle part without fingering diagrams, the same part but WITH fingering diagrams, the score, the separate piano part in case you need it, and a separate sheet which contains a comprehensive fingering chart. So if you enjoy playing the notes on the staff, there is a part for you! And if you need the diagrams for learning, or for using every time, there's a part for you!