BAJO QUINTO NICKEL STEEL LOOP & BALL END With its unique 10 and 12 string configurations, the Black Diamond Strings Bajo Sexto and Black Diamond Strings Quinto bass guitar strings deliver a dynamic range of sound that have become staples in Northern Mexican music. Treasured for their deep low-end projection as well as high articulation. Crafted to perfection for over a century, these strings add joyous energy to Tejano music with an unmistakable tone that is full of character.