Ernie Ball Medium Nickel Wound Electric Guitar Strings feature a wound G string and are precision manufactured to the highest standards and most exacting specifications to ensure consistency, optimum performance, and long life. All wound strings are made from nickel plated steel wire wrapped around a hex shaped steel core wire. Meanwhile, the plain strings are made of specially tempered tin plated high carbon steel producing a bright balanced tone. Gauges .013, .017, .026w, .034, .046, .056