The Republic of Srpska (also known as the Bosnian Serb Republic, one of two political entities in Bosnia & Herzegovina) is issuing (April 25th) two stamps featuring musical instruments: The fiddle and the dvojnice. A booklet (whose pane is shown on the right) includes both designs.

Here are the details provided by the Philately Department:

Europa CEPT – National music instruments – on 25. April 2014. There are 2 stamps in set (face values 1,00 KM or 0,51€ and 2,00 KM or 1,02€), booklet which consists of 3 sets (face value 9 KM or 4,60€).

Fiddle
Traditional string stringed instrument that is commonly used to accompany epic poems. It is an instrument Dinara area (Bosnia and Herzegovina, Montenegro and Croatia), Serbia appears at Kosovo Serbs and to some extent the Albanians.

Dvojnice
Dvojnice are popular brass instrument from the group labial played with an edge. These are actually made up of two tubes of the same length drilled in parallel. Each pipe has a hole of vocal cords and mouthpiece. The holes were drilled to have a pipe with four holes and on the other three.

A better explanation of what a dvojnice is can be found at Stjepan Večković’s Hrvatska Tradicijska Glasbala website. Basically, it’s one mouthpiece, connected to two different recorder-like pipes. One is made from wood, the other from brass.