A toy suling, duct flute, with external duct.
The suling is also known as a ring flute because a thin ring (in this case of bamboo) is secured round the top of the instrument. This is essential to its functioning because the duct that directs the air towards the sound producing sharp edge has the inside surface of the ring as its upper edge. The instruments are cheap to produce and so are often used as toys by children in Indonesia. Finely-crafted and tuned sulings feature in the Javanese gamelan orchestra of percussion instruments.