XL Nickel Wound electric guitar strings are the standard against which all other strings are measured. Our best-selling electric set, XL Nickel has been revered by players everywhere since 1974. Made with a high carbon steel core and nickel-plated steel wrap wire, XL Nickel strings have a bright, versatile tone, ideal for a wide variety of musical styles. With its 8.5 gauge high E, this 8.5-39 Extra Super Light Plus set offers a slight variation in tension, helpful to slowly transition to heavier gauges in small increments.