Pitch indicators are symbols used in musical notation to indicate the pitch of a note. The most common pitch indicator is the clef, which is a five-letter symbol that appears at the beginning of a staff line. Clefs are used to indicate the range of notes that will be used in a piece of music, and they can also be used to indicate the key signature. Different clefs are used for different instruments, such as treble clef for higher pitched instruments and bass clef for lower pitched instruments.