Martin M130 Silk and Steel Folk Guitar Strings | Light String Gauge: .0115, .014, .023, .028w, .038w, .047w Martin Folk offers the driving force of steel strings and soft tonal properties often associated with classical strings. A center wrap of silk fiber provides easier fingering and minimizes the brilliance for a sweeter and more mellow sound. For the Marquis we hand wrap silk around the ball end area to reduce wear on the bridge plate. Ball ends Tension: 122.2