Thomastik-Infeld Violin strings Infeld hybrid core - Set blue (IB100)Infeld "Red" The strings of the red and blue set can be combinated to change the soundcharacter without changing the string tension. The red series amplifies the dark sound of the instrument, the blue string maintains the brilliant sound. With E string chrome steel, gilded Composite Core = Hybrid core 4 4 Size Infeld Blue The strings of the red and blue set are combinable to change the sound characteristics without changing the string tension. The red