Martin MFX640 80/20 Bronze Acoustic Guitar Strings - Light Light Gauge: 012 .016 .025 .032 .042 .054 Martin FX 80/20 Bronze strings are made with bronzed steel core wire and bronze wrap wire. Great for new players, Finger-style pickers, Electric Guitar players not used to higher tension/heavier gauge acoustic strings. Great for shorter scale, high-quality acoustic guitars