Sutuli is a clay baked wind instrument. This half moon shaped, musical instrument fall under the category of Susira vadya (wind instrument) of Indian musical instruments. An indigenous folk instrument draws inspiration from nature. It emulates the sound of a wild bird-kuli in Assamese or more popularly known as ‘koel’ in Hindi. As dance groups gather in open spaces to celebrate arrival of spring during Rongali bihu, the sound of kuli, as many folk tales and folk songs suggest is the sound most sought amongst natives.
It is made of one type of special clay. Generally it is hollow half-moon shaped part. Its length is about 12 cm. Round shaped sutuli (diameter about 10cm) are also found in some villages. It has a hole in the middle to produce the whistling sound by blowing air into it. There are three holes on its body to control the tune, which the performer uses to manipulate the sound.
For more details: http://dsource.in/resource/popular-folk-musical-instruments