ELECTRIC GUITAR STRING KIT Electric guitar string sets D Addario NYXL1254 (12 - 16 - 20 - 32 - 42 - 54). D Addario NYXL guitar strings stretch more, sound louder, and tune better than any string you've ever played before. Conceived, refined, and manufactured by D Addario in New York, this newly designed, tear-resistant high carbon and smooth steel core provides a new level of freedom, confidence and power.