Product Reviews: Ton Kooiman "Prima" Flute Thumb Rest

Ergonomic adjustments are a personal matter depending on your hand shape so I'm just speaking from my own experience.
I bought this to add thickness to the flute so my (slightly backwards-curving) right thumb could grip less tightly, relieving tension where the thumb meets the wrist.
This rest is designed for players who hold the flute with their right thumb pointing forwards, not if your thumb points up towards the headjoint: the angle is adjustable but only by about 15 degrees. I tried it with the maximum adjustment possible but because my thumb was pushing up towards the head joint, it pushed the rest up the flute and the silicone band went under the back F connector. I'm now using it with the shield pushed on behind the positioning screw, which feels stable enough but I'll need to mark the position for reattaching the shield each time I get my flute out of its case. After some tweaking of the position of the baseplate on the flute it seems to be working as intended- a second Bo-pep for my right hand may have been a simpler option but this rest adds more thickness than any of the alternatives.

Unfortunately when attached to my flute the securing tabs interfere with my keys.
I have an intermediate Yamaha flute, which is such a shame because it’s just what I need.