These strings are produced under the highest manufacturing standards and strict control to ensure consistently high quality, durability, and maximum performance. Super Slinky Wound strings are made from nickel-plated steel, wound around a hexagonal steel core. The plain strings are made from specially hardened, tin-coated high-carbon steel, delivering a balanced tone. The strings come in the following gauges: .009, .011, .016, .024w, .032, .042.