D'Addario Helicore Viola String Set, Long Scale, Heavy Tension Long-scale viola (body length 16-16 1/2 inches) with a playing length of 15 inches (380mm) Heavy 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