Info from Manufacturer: 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.
.017 gauge nickel wound electric guitar string, round wound with nickelplated steel for distinctive bright tone. Perfect as a replacement string or for creating customized sets.

Made in the U.S.A. for the highest quality and performance.