Thomastik Infeld-Rot violin strings. State of the art synthetic core strings with perfectly matched tensions enable costumization of sound covering the entire tonal spectrum. Using Infeld violin strings, players can achieve tonal preferences in a single string brand without the headaches of uneven tensions. The Infeld-Rot strings reinforce the darkness of the sound. The Infeld-Blau strings reinforce the brightness of your violin's strings.