The gunjac (plural: gunjci) or bajs is a violoncello-like Croatian instrument but with only two strings. Gunjac instrumentalists are called bajsisti. It is a double bass string instrument played with a bow.
The gunjac is commonly found in melodic groupings (tunes) associated with North-Western and Central Croatia including the regions of Zagreb, Žumberak, Pokuplje, Upper Posavina, Moslavina, and Bilogora.
An international festival of bajs players is held annually in Draguć, Istria.
References
Gunjac Wikipedia(Text) CC BY-SA