Thank you for viewing. I am selling this because I changed instruments and no longer need it. If anyone would like to use it, please consider purchasing. This is a thumb rest with a ring for using a clarinet strap, made by B.AIR, a popular manufacturer of BIRD STRAP. *Screws, base, and instrument are not included. *Exclusively for ＜Buffet Crampon＞ clarinets. Can be used with instruments with a base manufactured before 2021. *Not compatible with Divine. *E13 and C13 require separate button screws. I used it for several years, but I don't mind the scratches. Please check the images.