Savarez 500CRJ Corum Cristal Classical Guitar Strings, High Tension, Red/Blue Card Cristal Corum Series^Mixed tension^Cristal clear nylon normal tension trebles, Corum silver plated wound high tension basses Trebles: Cristal Red trebles Normal tension Unpolished clear nylon Perfectly balanced with Corum basses Very flexible strings as fast and accurate as stiff strings, rich tone Great volume, easy playing 504J (4th string) 505J (5th string) 506J (6th string)