Hi @Gragonshandyman,
A warm welcome to the Bunnings Workshop community and thank you for your question.
There are quite a few that use the name Mondella Resonance mixer. Can you advise which specific sink mixer you have?
Most sink mixers require a 35mm hole, but I'd like to confirm with the specific model to be certain.
When you let me know, I will confirm with the installation manual to ensure you have the correct information.
Jacob
