Dare to be different. Bluegrass is one of America’s finest traditions and its instruments demand strings with dynamic response and brilliance. The nickel and steel alloys used in our dulcimer strings bring out the unique sound in these oh so unique instruments. Martin Dulcimer strings are made with tin plated steel core wire and tin plated steel wrap wire. Set: M640 Gauge: Standard 12-12-12-22 Tension: 67.9 Package: 4 strings