This is a Vandoren synthetic reed for Bb clarinet. The synthetic reed "VK1" is made of a new composite fiber created by Vandoren after 7 years of research. This new composite fiber does not simply imitate the structure of cane. It reproduces the essential physical properties of cane to achieve the same acoustics as cane reeds. I purchased a strength of 3.5, but it was too hard for me, as I usually use V21 2.5. I have only used it for testing. The other synthetic reeds are Légère. The strengths are 2, 2.25, and 2.5. I haven't used these much either. Thank you.