Everlast Coated Acoustic Strings use groundbreaking nanotechnology that repels unwanted moisture and oils that negatively impact your tone. Made from 80% copper, 20% zinc wire wrapped around hex shaped tin plated steel core wire. The most popular acoustic guitar string material provides a crisp, ringing sound with pleasing overtones. Gauges: .010, .014, .020w, .028, .040, .050