Quasar clone o-rings

[dw117]

I have a quasar clone and the bottom o-rings that keep the top cap assembly on the deck are just rubbish. They flake off and come out of place all the time so I was going to get some replacements.

Has anyone had any experience of this and can help? As far as I can tell from measuring I think I need 19mmx17mmx1mm o-rings and I can find a few sellers on ebay with them.

Thanks.