The EXL150 set is the most popular choice for 12-strings guitars, providing the ideal balance of comfortable feel and bright, jangly tone. XL Nickel Wound, D'Addario's most popular electric guitar strings, are precision wound with nickelplated steel onto a carefully drawn, hexagonally shaped, high carbon steel core. The result, strings with long lasting, distinctive bright tone and excellent intonation, is ideal for the widest variety of guitars and musical styles.