Question Expanding RAM in my Alienware - which memory should I buy?

[eddified]

I have 1 stick of 16GB RAM in my Alienware R12. I have 4 slots total (3 open). I'd like to buy one more stick. What should I buy? Amazon/NewEgg links are welcome.
Would this be fine? (I just searched "Kingston DDR4 3200 16GB". Not sure if I should be filtering it down by some other specs too?) I'm not very experienced at computer hardware selection, especially memory.

Edit: Hm, no, the link I provided before says "notebook memory". My machine is not a notebook.
Edit: how about this one? It says "CL22". I'm not sure, do I have to buy CL20 because my current ram says "CAS# Latency (CL): 20.0 clocks".

 

[SkyNetRising]

Edit: how about this one? It says "CL22". I'm not sure, do I have to buy CL20 because my current ram says "CAS# Latency (CL): 20.0 clocks".

That won't work either. It's registered ram - for servers.

 

[SkyNetRising]

I'd suggest you get a dual channel kit instead 2x16GB and replace your existing ram module.
Modules in kit are tested for working together.
Mixing separately purchased modules can lead to ram compatibility issues.

https://www.newegg.com/p/pl?d=kingston+ddr4+16gb+3200+desktop