Traditional reeds (blue box) are available in strengths 1 to 5 (1, 1 1/2, 2, 2 1/2, 3, 3 1/2, 4, 5) The most widely played reeds in the professional world, with a superiority proven over many years, these reeds suit all styles of music. The principal acoustic qualities are: Excellent response in all registers, even allowing a pianissimo attack of the highest notes. Flexibility allowing the legato or staccato execution of large intervals. A richness of tone which gives body and brilliance to the sound. Thickness at the tip: .09mm (0.0035 inch) Thickness at the heel: 2.8mm