Check the listing for details. Thomastik-Infeld S31 Spirocore Cello String Set. Condition: New. Listed at 226.55 USD. Cutting-edge Cello Strings Cellists need strings that are highly responsive and long lasting. That's why so many professional-level musicians turn to Thomastik-Infeld — their cutting-edge Spirocore cello strings deliver both. Spirocore strings vaunt ultra-flexible multiwire spiral rope cores, which imbue them with superior musical vibration and reduced inertia. Cellists at Sweetwater have found Spirocore strings to sound great for a myriad of playing situations. Whether you're performing a smooth arco passage or a circus-like cacophony of pizzicatos, these strings make everything you play sound incredible. Thomastik-Infeld has been producing high-end orchestral and fretted instrument strings for more than 100 years, and Spirocore cello strings are among their best.