Specifically designed to solve open E-string whistling. Produces a warm, rich tone that blends very well with lower strings. Free ball end adapter included! Playing length 328mm, Tension 18.6 lbs. The introductory string in this series eliminates the whistling sometimes heard when the open E string is played while crossing from a lower string. Its unique design comes from intense scientific study, and the result is a string that not only eliminates the whistle, but produces a sweeter sound that better matches the sound quality of lower strings!