D'Addario H313 4/4M Helicore Violin Single D String, 4/4 Scale, Medium Tension Scaled to fit 4/4 size violin with a playing length of 13 inches (328mm), these medium tension strings are optimized to the needs of a majority of players. The E string included with the H310 set is a plain steel E (tin-plated high-carbon steel) with no winding. Packaged in uniquely-designed sealed pouches providing unparalleled protection from the elements that cause corrosion. 4/4 scale violin with a playing length of 13 inches (328mm) Medium tension Stranded steel core provides optimum playability and produces a clear, warm tone Versatile string that works well for a wide variety of playing styles and instruments All D'Addario strings are designed, engineered and manufactured in the USA to the most stringent quality controls in the industry