SPIROCORE cello C string,With Spirocore strings, the ground breaking innovation of an ultra flexible metal spiral core was perfected by Thomastik Infeld in 1957. They rank among the most used cello strings due to their unsurpassed responsiveness, lifespan and sound. The set Spirocore S31 represents a technical revolution of the early 1950s. Its strings spiral rope core has a much greater elasticity and therefore a higher vibration capacity with less damping than other rope