What are these for?

[Deniedstingray]

Just a random question for you guys, What are the three different sized holes for on the back of my pc's case under the exhaust fan.

https://www.google.ca/search?q=commander-g41+back&source=lnms&tbm=isch&sa=X&ved=0ahUKEwijh9_pgpPSAhWmrVQKHRQ9DWgQ_AUICCgB&biw=1920&bih=928#imgrc=TmbQ3VS40VwaXM:

 

[Dark Lord of Tech]

Water cooling options.

 

[dangus]

supposedly theyre cutouts for water cooling tubing....which i dont think anyone has ever used in the history of the earth ever.

 

[Deniedstingray]

Water cooling options.

Ah, makes sense. Thanks for the reply!

 

[Dark Lord of Tech]

Glad to assist.

 

[Sm0k]

Yep SR-71 is right, here is an example of it http://modding.lt/client/files/c_items/127114318469.jpg

 

[Eximo]

Not the best example ever.

You see some people put the pump/reservoir on the outside. Or have a separate radiator only chassis that sits on top of the system.

Others use them as drain and fill ports.