Sandblasting Cabinet 4 3/4" Fan mount

This is for the Power Fist Sandblasting cabinet to add a fresh air fan to the back of the cabinet. The fan was also purchased at Princess Auto 4 3/4"x1.5". It often goes on sale.
Plus additional attachment parts to vent this with 2" ABS.
The back of this fan will snap into the rubber ring on the back of the cabinet and require no other support to hold it in.
Here is the fan I purchased, just so you can find something similar:
https://www.princessauto.com/en/detail/4-3-4-in-square-fan/A-p8012