The suling (Soo-ling) is a bamboo flute native to a wide range of countries in Southeast Asia. It is included in the gamelan music of Indonesia, most notably Balinese and Sundanese (from Java) styles. It is an end-blown flute, and the sound is produced by the breath stream splitting over a reed wrapped around the end of the instrument.
The suling pictured here was made in Java, and is tuned to what is often called the "Balinese" pentatonic scale (though there are likely thousands of different scales and tuning systems in use on Bali, this is one of the most recognizable). It is  relatively analogous with the 1,3,4,5, and 7 of a major scale (C,E,F,G,B, for example). Notably, this scale can be heard in the Beatles song, "Within You Without You".