I posted this in the washer bottle grommet topic.
You could make your own. I bought some round section O-ring material for a job a while back. Cut to length for the circumference you need and superglue to connect the ends. I have a box of O-rings but none fitted so bought the right diameter( thickness). If I remember correctly it was sold by the metre and not expensive. I’ll see if I can find details. A google search is another option.

Plus Four MY23 Furka Rouge