Two kinds of instrument are almost universally present in the musical performances of this latter people: the armpit drum which they call dumanu (in the Bomu language), and another small two-skinned drum called an i'izo, not as long as the first and whose cylindrical wooden frame is not gashed. These two instruments, generally played together, are part of the make-up of other groups of instruments such as xylophones (which the Bwa call cooza) whose curved shape resembles that of the xylophones of Central Africa. This shape distinguishes them from the Bamanan xylophone, the large drums and the frames.