Pirastro Original Flexocor Bass Strings*Basic Trial Sets limited to 2 per customer* Features The core material is a high tensile rope made from carbon steel which is wound with chrome steel. This is an outstanding set for arco, which can withstand a powerful and heavy bowing arm. brilliant sound with a short sustain powerful sound with great projection big tone volume instantly playable and absolutely stable very quick response, which is slightly quicker than Original Flat Chrome Pirastro