This is a Savarez 520R Red Card Rectified Nylons Traditional Basses normal tension nylon guitar string set with gauges: 28-32-40-30-34-42.

Savarez Traditional trebles are made of rectified nylon which is characterized by a distinctive unpolished finish. This grittiness contributes to a lessening of the high overtones. Because of their texture, the treble strings are unusually controllable with regard to vibrato and stability. The characteristics of their tone make their pitch particularly clear and true. The basses are on the warm and soft side, and their tone is strong overall.