XL ProSteels are D’Addario’s brightest electric guitar strings. The unique, highly magnetic alloy in ProSteels offers a super bright, crunchy tone, and increased sustain. Made with a high carbon steel core and stainless steel wrap wire, ProSteels produce enhanced interaction with magnetic pickups, creating an extraordinarily bright tone that will cut through any mix. These 11-50 Medium gauge strings provide increased volume, with slightly more tension and resistance.