The K3 Black Beauties from DR Strings are black-coated electric guitar strings utilizing the proprietary and patent-pending K3 Technology Coating to deliver strings that have more volume, less unwanted overtones, and greater clarity and articulation than uncoated strings. Additionally, the coating provides protection from corrosion and perspiration, as well as increased tone life. The pack contains six medium-gauge nickel-plated on hexagonal-core strings (10, 13, 17, 26, 36, 46). Like all DR Strings, the K3 Black Beauties are handmade in the USA from all-American materials.