Octave key

The octave key is a key on a saxophone which raises the pitch of all notes by an octave when pressed. It is positioned next to the left thumb. The presence of this key is one of the main features which makes the saxophone easier to play than the clarinet, because the same fingerings can be used for two different octaves. The analogous key on the clarinet, the register key raises the pitch by an interval of a twelfth (19 semitones), making the fingerings different for low notes and high notes, which are an octave apart.