These instruments are one of the many types of instruments constructed using the local bamboo. These bamboo rattles are pitched in such a way as to create unique melodic "woody" tones. This particular set goes through 3 octaves. Angklung is usually played by a group of 20 to 40 people. This group of people lead by a conductor.
In 1998, Agus Hardiman with his innovative work invented THE ELECTRIC ANGKLUNG (an instrument consisting of rows of Angklung bamboos arranged in a way that it resembles a piano).
Photo courtesy of Agus Hardiman
Below is a sample of angklung music produced by that instrument (in Real Audio format):