Martin Traditional strings are our flagship line that stands the test of time. Tried and true, they are designed to deliver consistent quality and tone with every set. Great for daily play and appropriate for all skill levels, our Traditional 80/20 Bronze acoustic guitar strings are made with bronzed steel core wire and bronze wrap wire. Set: M150 Gauge: Medium 13-17-26-35-45-56 Tension: 181.1 Package: 6 strings