Rosewood thumb piano, 3" x 5", 8 steel keys. The thumb piano originates in Africa. It is also known as the mbira or likembe. The metal keys are mounted on a wooden box that acts as the resonating chamber. Longer keys have lower pitches and shorter keys have higher pitches. The keys can be adjusted by tapping them in or out to adjust their pitch. Many different tunings are acceptable, according to personal preference. Similar tuning is only an issue when two instruments are played together; then they should generally agree in tuning.