Thomastik-Infeld S42 Spirocore Bass Strings, Complete Set, 4/4 Size, Orchestral Tuning These top-grade, hi-tech Thomastik-Infeld S42 Spirocore Upright Double Bass Strings - 4/4 Medium are renown for the ease of their playability and their distinct sound."Spirocore's hi-tech core makes for effortless fingering, responsive bowing, stable tuning and a very long string life. With Spirocore the steel string's technical possibilities have been developed to their maximum." - Thomastik-Infeld Thomastik-Infeld S42 Spirocore Upright Double Bass Strings - 4/4 Medium offer a full, balanced and voluminous sound with a flexible multi-wire spiral rope core (Spirocore) that make the string highly responsive and long lasting. Less inertia means a longer period of musical vibration making these strings equally effective for playing arco or pizzicato. Note: Bassists with a low C extension love this string's reliability. Jazz bassists also love the Spirocore because its compatibility with an amplified pickup. Spirocore also addresses 'cello issues like wolf notes and muting difficulties by winding the C and G strings in tungsten and silver wound.