On a pipe organ, these are open, metal stops that play at intervals above the fundamental (or tonic). As an example, a Twelfth sounds an octave and a fifth above the root note and would be considered 2-2/3′ in length and pitch. The Seventeenth sounds two and a third above the root note. Length and pitch would be 1-3/5′. Where such stops appear on the pedal, their length and pitch are doubled and often quadrupled.