These thumb rests are ergonomically designed to ease stress on your thumb. They are permanently fit to the clarinet, using existing screw holes, with a back plate. The thumb rest is inter-changeable between A and Bb.
Ton Kooiman understands the ergonomic issues musicians face: like top athletes, instrumentalists are constantly involved in trying to get the maximum output from the energy and effort that goes into performing on their instrument, while at the same time maintaining a free and natural playing posture and a perfect technique. The Ton Kooiman thumb rest is for both children and adults: large and small hands: for every type of player (amateur or professional). Who would like to play, and continue to play, with less physical fatigue and much improved results.