Two pipes (one large, one small) connected to form a transverse flute with a duct. The mouth hole is at the lower end of the small pipe and the flute hole is on the back of the large pipe. The two pipes are connected by a thin pipe, 2.5cm long. The player's breath passes through this pipe, thereby reaching the long pipe. A piece of wood 3.3cm long is wedged into the upper end of the long pipe, forming a duct. The instrument is used to reinforce the lower pitches of the siku.