EJ48, hard tension, features 80/20 bronze wound basses for bright acoustic tone, comfortable feel and dynamic projection. All Pro-Arté treble strings are computer controlled by an X-Y laser microscope which performs diameter and tension measurements, ensuring true-sounding, precise trebles in every set. Pro-Arté basses are wound using silver-plated copper on a multi-filament nylon core for consistent and warm, yet projecting tone.