D'Addario EJ21 Nickel Wound Electric Guitar Strings, Wound 3rd, Jazz Light 12-52 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. D'Addario XL Nickel Wound strings are precision wound with nickelplated steel on a hex-shaped core, resulting strings with a distinctive bright tone and excellent intonation String Gauges: Plain Steel .012, .016, Nickel Wound .024, .032, .042, .052