EJ43 is the lightest tension available of D'Addario's best selling Pro-Arte series. Great for beginners or experienced players with a lighter touch, they provide ease of play without sacrificing rich tone. EJ43's contain silver wound on nylon bass strings with clear nylon trebles. Pro-Arte, the world's most popular classical strings are D'Addario's premium classical guitar string sets. All Pro-Arte treble strings are sorted by a sophisticated computer-controlled laser machine which performs diameter and tension measurements, ensuring true-sounding, precise trebles in every set. Pro-Arte basses are wound using silver-plated copper on a multi-filament nylon core for consistent and warm, yet projecting tone. Light tension version of the best selling Pro Arte series Laser sorted clear nylon treble strings for consistent, precise intonation Precision wound basses for warm, projecting tone and the utmost consistency Made in the U.S.A. for the highest quality and performance String Gauges: Trebles .0275, .0317, .0397 Basses .028, .033, .042