ELECTRIC GUITAR STRING SET Electric Guitar String Set XL Series Nickel Wound Jazz Medium ((13 - 17 - 26 - 36 - 46 - 56). D'Addario XL Strings for Electric Guitars have been recognized worldwide as '' The Option Guitarist '' among guitarists of all genres and styles.XL strings are precision-wound with nickel-plated steel over a hex-shaped core, resulting in strings with a distinctive, brilliant tone and excellent intonation.