Gauges 28-32-41-30-36-44. All DAddario Pro-Arte treble strings are measured by a sophisticated computer controlled laser which performs consistency and quality checks, insuring true sounding trebles in every set. Basses are made from Silverplated Copper wound on Nylon. DAddario is the worlds largest manufacturer of strings for musical instruments. Many top guitarists wont play any other brand. Regardless of your playing style, DAddario has a set of strings thats right for your classical guitar.