MAMMOTH SLINKY NICKEL WOUND ELECTRIC GUITAR STRINGS - 012/062 GAUGEErnie Ball Nickel Wound Electric Guitar Strings are made from nickel plated steel wire wrapped around tin plated hex shaped steel core wire. The plain strings are made of specially tempered tin plated high carbon steel producing a well balanced tone for your guitar. Gauges .012, .016, .024w, .034, .048, .062