D'Addario EJ16 Phosphor Bronze 12-53 Light Acoustic Guitar Strings - 10 Pack D'Addario Phosphor Bronze Acoustic Guitar strings are acclaimed worldwide for their great, long-lasting tone. Phosphor Bronze was introduced to string making by D'Addario in 1974 and has become synonymous with warm acoustic tone. String Gauges: Plain Steel .012, .016, Phosphor Bronze Wound .024, .032, .042, .053