EJ45 Pro-Arte - A normal tension classical nylon string set. Great for the beginner to intermediate player and for guitars with a particularly tight feel. 1 E 0.028 2 B 0.0322 3 G 0.0403 4 D 0.029 5 A 0.035 6 E 0.043 Pro-Arte strings are our the world's best selling and D'Addario's premium classical guitar strings. All Pro-Arte treble strings are sorted by a sophisticated computer-controlled laser machine which performs diameter/tension measurements and quality checks, insuring true sounding, precise trebles in every set. Pro-Arte basses are wound using silverplated copper on a multi-filament nylon core for consistent, warm-yet-projecting tone.