Ton Kooiman thumb rest "Etude3" for clarinet, black, the Etude makes it possible to move the pressure point of the thumb rest to the first phalanx of the thumb to the space between the two joints. The mounting slide can be attached to your instrument with the screws provided for. But into the "old" already existing holes of the factory thumb rest. So no new holes drilled here! The metal hook is covered with soft rubber and a casing with improved ergonomics.The hook is adjustable in height as well.