This is a new version of my Raspberry Pi Noctua 40mm fan mount, with the top redesigned to work with a Raspberry Pi 4.
In addition to these parts and a 5V Noctua (or other) 40mm fan, to put this together you will need 4 x M2 25mm bolts and 4 x M2 nuts, plus 4 x M3 12+mm bolts and 4 x M3 nuts to secure the fan. Oh, and you'll need some sticky feet for the base it you want to, well, stick some feet on the base.
This thing is featured in this ExplainingComputers YouTube video : https://www.youtube.com/watch?v=AVfvhEJ9XD0
I had both parts printed online in PLA. All worked fine.