ELECTRIC GUITAR STRING SET String Set for XL Series Electric Guitar Nickel Wound Super Light Top / Regular Bottom (009 - 011 - 016 - 026 - 036 - 046). D'Addario XL Electric Guitar Strings have been recognized worldwide as '' The Guitarist's Choice '' among guitarists of all genres and styles. XL strings are precision wound onto nickel plated steel over a hexagonal shaped core, resulting in strings with a distinctive, brilliant tone and excellent intonation.