Corelli CO-375-F double bass string C-5 4/4-3/4, heavy, rope core, tungstenCorelli CO 375 F double bass string C 5 4 4 3 4, heavy, rope core, tungsten These strings are the result of several innovating technologies applied to their composition and winding process. Since they have a thinner gauge, they are very flexible and very easy playing, and have a quick response. The high precision of their diameter, obtained thanks to advanced computer techniques, associated with the use of the laser, offers a perfect tuning accuracy.