These strings are factory specification strings used at the Gibson USA facility and were developed and approved by Gibson Master Luthiers. The strings feature a hex-shaped core made of high-carbon steel, which provides superior durability. The core is precision-wound with nickel-plated steel, which produces a powerful tone and sustain. The strings are available in three different gauges: Ultra-Light, Light, and Medium, and each gauge contains six strings with varying thicknesses to accommodate different playing styles. The Ultra-Light gauge includes string thicknesses of .09, .011, .016, .024, .032, and .042. The Light gauge includes string thicknesses of .010, .013, .017, .026, .036, and .046. The Medium gauge includes string thicknesses of .011, .014, .018, .028, .038, and .050. These strings are known for their bright, crisp attack and superior sustain, making them suitable for a wide range of musical genres and playing styles.