Good evening
I have not found any suitable rubber rings among the Weck articles.
But under the article no. 55685639
Tala sealing ring set, 9cm diameter, 6 pieces
I have found an article that might fit.

I personally bought the tumblers to make desserts that I can tumble.

I hope I have been able to help you.

Kind regards
A. Bolt

The matching rubber rings are item no. 8036551 with a diameter of 8 cm.