Helicore strings have a multi-strand high-carbon steel core that produces flexible response and range. 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. Offering a warm, rich sound; D"Addario Helicore viola strings are a fantastic string used by classical musicians and fiddlers alike. The multi-strand, high-carbon steel core unique to Helicore strings produces flexible response and range. Unlike gut, however, Helicore strings are impervious to fluctuations in humidity and temperature.