Gauges 09-13-21-29-36-45D'Addario EJ41 12-String Phosphor Bronze Extra Light Acoustic Guitar Strings are durable and possess a bright, penetrating sound. D'addario strings retain their brilliance long after similar bronze and brass alloy strings go dead. D'Addario is the world's largest manufacturer of musical instrument strings. Many top guitarists won't play any other brand. Regardless of your playing style, D'Addario has a set of strings that's right for you and your guitar.