Jacuzzi Flexa Tower jet knob replacement

The Jacuzzi Flexa Tower is a wonderful shower cubicle offering many functions, like hydromassage jets, steam bath and a fantastic water cascade. The 24 adjustable jets use round 'ring knobs' that allow the user to change the shape of the water jets. These rings have a tendency to split after a couple of years, possibly due to mineral build up. When they split they can't grip the nozzle sufficiently anymore. Enter the solution: print your own!
This replacement part has been designed to be easily printable and offering the same function as the original part. However it's not an exact copy of the original part. Printing them in transparant PETG imho creates a nice looking replacement part that should be a lot stronger than the original. :-)