Dvojnice, double duct flute. Left-hand pipe with four fingerholes, right-hand pipe with five.
The dvojnice is associated with folk music cultures of the Balkans. Its ability to play an independent melody on each pipe allows it to imitate polyphonic vocal styles, with each pipe representing an individual singing voice. The number of holes on the two pipes varies between regions. This Bosnian example has four holes on the right pipe and three on the left, but in Herzegovina it is more traditional to have four holes on the right pipe and three on the left.