What kind of disk is in front of the RAM bar and is it necessary?

ra
2

I've watched some videos of people disassembling their laptops to add more RAM. And in the process I always came across these RAM bars that have such a gray plate stuck on both sides. I checked and my already installed latch also has these panels in front of and behind the latch. The bar that I bought new to expand my RAM, however, does not have such plates sticking on both sides. Is that somehow important for them to work?

What kind of disk is in front of the RAM bar and is it necessary
Ge

Should be a cooling

de

Is a cooling. If your RAM does not have 4000 MHz, cooling is not necessary.