EJ21, D'Addario's most popular round wound "jazz" set, features; wound 3rd/G string for greater resonance and; tighter feel. Can also; used for down tuning; Nickel Wound, D'Addario's most popular electric guitar strings, are precision wound with nickelplated steel onto; carefully drawn, hexagonally shaped, high carbon steel core. The result, strings with long lasting, distinctive bright tone and excellent intonation; ideal for the widest variety; guitars and musical styles; Features; wound 3rd/G string, optimal for "jazz" style playing and some drop tunings Round wound with nickelplated steel for distinctive bright tone Environmentally friendly, corrosion resistant packaging for strings that are always fresh Made in the U.S.A. for the highest quality and performance String Gauges: Plain Steel .012, .016, Nickel Wound .024, .032, .042, .052