Everly 7311 Red Brand Ac Cust Lt 11-52 Gauges: 11-15-024w-32-42-52. This is the first brand of copper/bronze acoustic guitar strings These strings contain the highest copper content of any acoustic guitar string-more than 80/20, more than phosphor bronze Red Strings provide precise articulation, louder sound, great projection, and a warmer richer tone from the moment you tune them up There hasn't been a significant new material introduced for acoustic guitar strings in 35 years