D'Addario Helicore strings are crafted with a multi-stranded steel core, making for optimum playability and producing a clear, warm tone. The smaller string diameter provides quick bow response. Premium quality materials combine with skilled workmanship to craft strings with excellent pitch stability and longevity. The core is overlaid with exotic alloy windings that provide extremely quick bow response and outstanding projection. The end result is a versatile string with very long playing life that is extremely stable under all playing conditions. (All sets are MEDIUM GAUGE, unless specified otherwise)