D'Addario Zyex Violin Single A String, 4/4 Scale, Medium Tension 4/4 scale violin with a playing length of 13 inches (328mm) Medium tension Zyex synthetic core produces a rich, warm tone Short break-in time and excellent bow response provides superb playability and a broad tonal palette All D'Addario strings are designed, engineered and manufactured in the USA to the most stringent quality controls in the industry