My first question was not accurate... I am trying to find a 8.25 inch, plastic, replacement cover for a bathroom exhaust/light fan... Was installed in 1990...
Do not know the brand. I thought I had found one that was 8.25 inch, but, it had 6 little nubs, whereas I need one with 3 nubs to fit into the 3 holes in the housing...

Wouldn't it be better to replace the fan with a new one if it's that old.