The so sahm saai has three strings and is the hardest to play among the different types of traditional fiddle-like, bowed string instruments, such as the so and so.

Due to this, it is frequently used to show off ones knowledge or high social status, and well-off musicians often have their instruments custom-made from superior materials. This one, made from ivory and elaborately carved into a dragon head and decorated with gold, was commissioned for King Prajadhipok (Rama VII).