Introducing RED. The first brand of Copper Bronzeacoustic guitar strings. With the highest copper content of any stringmaterial - more than 80/20 and more than phosphor bronze - RED Stringsgives acoustic guitars precise articulation, louder sound, greaterprojection and a warmer, richer tone from the moment you tune them up.There hasn't been a significant new material introduced for acousticguitar in 35 years.