EJ46, hard tension, is a popular choice for its rich tone, increased resistance and strong projection. 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. Hard tension for increased resistance, volume and projection 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 .0285, .0327, .0410 Basses .030, .036, .044