D'Addario Kaplan Cello StringsCreated with the most discerning and astute musicians in mind, the Kaplan cello string yields a complex and rich tone. The solid steel core allows a performer to generate a powerful and projecting sound that is also rich, clear, and warm. The steel core also allows the string to stand up to intense bow pressure. All D'Addario strings are manufactured, designed, and engineered in the USA to some of the highest quality control standards in the industry.