"The concheros string instruments are Mexican plucked instruments that consist of three variants:mandolino de concheros or mandolina conchera: with 4 double courses (8 strings)vihuela de concheros or vihuela conchera: with 5 double courses (10 strings)guitarra de concheros or guitarra conchera: with 6 double courses (12 strings)In their structure these instruments have a concha (armadillo shell), a shell-like wood body or a gourd as resonance box."@en . . .