Strings for electric guitar. EPS540's offer a super-bright, crunchy tone and corrosion resistance for longer string life. D'Addario XL ProSteels utilize an exclusive corrosion-resistant steel alloy that delivers super-bright tone without shrill overtones. They offer a palette of harmonically rich, brilliantly penetrating highs combined with pronounced, tight-and-tough lows. Light Top/Heavy Bottom gauge. Gauges:. 010, . 013, . 017, . 030, . 042, . 052