Thomastik Superflexible Violin Strings 4/4Thomastik Superflexible strings feature a multi strand steel core offering superior flexibility and tonal response. Thomastik Infeld Superflexible violin string's solid core has been replaced by a cable type structure made up of braided steel threads. Thomastik Superflexible strings feature a multi strand steel core offering superior flexibility and tonal response. Thomastik Infeld Superflexible violin string's solid core has been replaced by a cable