It was developed with a focus on the hard rubber thumb rest, which had a significant influence on the thick, dark tone of the early Selmer Mark 6 models manufactured from 1954 onwards. Hard rubber is used even for the screws, so vibrations are not hindered, resulting in a smooth sound and a mild tone with soft overtones.- Made of hard rubber - For Selmer and Yamaha only (cannot be used with Yanagisawa guitars)・Soprano, alto, tenor and baritone compatible ----- *If you wish to remove the product, shipping costs will be borne by the customer. *Processing may be required depending on the age of the instrument being installed. * In most cases, the thumb rest that comes with your instrument is glued in place. Trying to remove it forcefully may result in scratches or damage. *Not only the thumb rest itself, but also the screws themselves are made of hard rubber. This is a very delicate material, so please handle with care. *When adjusting screws, please use a flat-head screwdriver that matches the size of the screw. *The elasticity of the screws will keep them firmly attached to the instrument, so please be careful not to tighten them too much.