Wong khrueang sai is a musical ensemble in Thai classical music which consists primarily of string instruments. A typical khrueang sai ensemble features two two-string fiddles, one high and one low, a three-string zither called jakhe, a vertical duct flute called khlui, hand drums, and various cymbals. Depending on the size of the ensemble, instruments may be doubled or left out. A three-string spike fiddle called saw sam sai may be added as well. The khim has become popular and is also used in this ensemble. In the 20th century, Western instruments such as the violin or organ have also occasionally been integrated into khrueang sai ensembles.