Providing thick strings for the bottom and thinner gauges for the top, Ernie Ball's Skinny Top Heavy Bottom Slinky Nickel Wound Strings are intended for use with six-string electric guitars. Each wound string features a tin-plated high-carbon steel hex core wire wrapped with a nickel-plated steel wire, while the plain strings are made of specially tempered tin-plated high-carbon steel. The resulting set provides a warm and balanced tone.