Martin M140 80/20 Acoustic Guitar Strings, Light 3 Pack M140 80/20 Light Acoustic Guitar Strings 3-Pack "Martin M140 Light Acoustic Guitar Strings have an 80/20 composition for brilliance, clarity, and longevity of sound The Bronze winding alloy is ideally suited for making strings have deep, rich basses and clear, bright trebles The Martin M-140 acoustic pack has high-quality strings for daily use Core and wrap wires meet strict requirements to make the grade