The composition of a morna band is not rigid. A medium-sized band may have, besides the aforementioned guitar, a cavaquinho (that plays the chords rhythmically), a ten or twelve string guitar (popularly called “viola” in Cape Verde, that provides an harmonic support), a solo instrument besides the singer's voice and some percussion instrument. A bigger band may have another guitar, an acoustic bass guitar, more than one solo instrument (violin, clarinet, trumpet, etc.) and several percussion instruments (shaker, güiro, bongos, etc.).