Gauge: .46. Pro-Arte Classical Guitar strings are D"Addario"s premium classical guitar strings. Treble strings are measured by a sophisticated computer-controlled laser which performs consistency and quality checks, insuring true-sounding strings in every set. Basses are made with 80/20 bronze wound on nylon. D"Addario is the world"s largest manufacturer of strings for musical instruments. Many top guitarists won"t play any other brand. Regardless of your playing style, D"Addario has a set that"s right for you.