Martin M240 80/20 Bronze Bluegrass Medium Light Acoustic Guitar Strings (Discontinued) Leave a Comment / Uncategorized / By Denise / September 13, 2017 91GEARANK 91 out of 100. Incorporating 70+ ratings and reviews. Street Price: $3.59 Manufacturer: Martin FeaturesSet: M240Gauge: Bluegrass 12-16-25-35-45-56Tension: 176.9Package: 6 strings