This 5-note chromatic expansion set is designed to complement the diatonic 8-note set. When combined, it creates a complete 13-note chromatic octave, offering greater musical range and flexibility.
 
The Push Pumps produce sound when air is pushed through the internal reed by pressing the hand pump, creating clear and responsive tones.
 
Designed for tabletop use, the instrument can be played by pressing or striking the centre top surface. Different playing techniques allow for expressive musical control — slow presses create sustained notes, quick presses produce short sounds, firm presses generate louder tones, and gentle presses create softer dynamics.