I designed them to use #6x1/2" wood screws, but you can use appropriate plastic screws. I used my old 200mm fan from my antec ninehundred from over a decade ago. I've been hanging on to that large fan for a long time so it's good to finally reuse it and appreciate that it didn't end up in a landfill. I like to save fans, buttons, power supplies, I sometimes clip the usb cords off broken devices before tossing them.
I used this to cool my networking peripherals. It should extend the life and prevent thermal throttling, they run hot.
The author marked this model as their own original creation.