The document discusses treble and bass clefs. It explains that the treble clef, also called a G clef, is used for higher-pitched instruments like the flute and violin. The bass clef, also called an F clef, is used for lower-pitched instruments like the bassoon and cello. It notes that the piano uses both clefs since it can play notes across a wide range of pitches. The document also illustrates the notes in each clef, with the treble clef containing notes from G to G above and the bass clef containing notes from B to B below.