DAddario J910MM Prelude Viola Medium Scale Prelude viola strings are solid steel core strings, unaffected by temperature and humidity changes, and have excellent bow response. Prelude strings have the warmest sound available in an economy, solid steel core string design. Prelude is the educators preferred choice for student strings due to their unique blend of warm tone, economy, and durability. Medium scale strings are gauged specifically to fit medium-scale viola (body length 15-15 3/4 inches) with a playing length of 14 1/8 inches (360mm).