Assertion: flute's key | /r/HasProperty | long f
Facets:
Source sentences:
text: Two keys (long F and high C) can be added to improve playability, and two more keys (low C and C#) can be added to extend the range of the instrument to middle C.
text: Some flutes include a sixth key known as the "Long F" key which provides alternative fingering which may be useful in certain passages of music.