EJ21, D'Addario's most popular round wound "jazz" set, features a wound 3rd/G string for greater resonance and a tighter feel. Can also be used for down tuning. Features a 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