Screws for the Noctua NF-A4x20 fan

I have bought the “Noctua NF-A4x20 5V PWM” in Amazon (https://www.amazon.es/gp/product/B071FNHVXN). It is a product selled in Amazon by Noctua Austria. Although you can see in the description 5V, they sent me the 12V version. I could see that there were no screws in the kit, so when I return the 12V version and buy the 5 V version, I will have to buy some screws to attach it to my Jetson Nano.
I have read that the height of the 5V fan is 20mm (12V’s height is the same as I see).
https://noctua.at/en/nf-a4x20-5v-pwm/specification
So, if you use a 16 mm M3 screw (as I read in some other forum topics), you are going to get short, aren’t you?
Can somebody that has a “Noctua NF-A4x20 5V PWM” mounted over a Jetson Nano help me?

Thanks in advance.

The 5-volt fan is in the same housing as the 12-volt fan, and you can see that
a shorter screw can be inserted at each corner. I used 10mm self-tapping M3 screws.
Length was not the problem for me. I found it very difficult to screw the screws
into the heatsink, and I may go back and use a tapping tool on the heatsink to make
a threaded hole, and get some screws that actually fit.