D'Addario's best selling Pro Arte set, Normal tension offers balance of volume and comfortable resistance / Laser sorted black 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 .0280, .0322, .0403 Basses .029, .35, .043 / Environmentally friendly, corrosion resistant packaging for strings that are always fresh