From D'Addario:

NYXLs will bend farther, sing louder, and stay in tune better than any string you’ve played before. As our premium uncoated electric string, NYXLs offer higher break strength, enhanced tuning stability, and accentuated mid-range frequency response, providing more presence and crunch to cut through the mix. Made with a NY Steel core, premium nickel-plated steel wrap wire, and Fusion Twist technology, NYXL electric guitar strings are tough enough and versatile enough to handle anything. 11-49 Medium gauge strings provide increased volume, with slightly more tension and resistance.