[SOLVED] Are cable extensions safe?

[MoeSkeetToe]

I want a nice look for an upcoming build but I don't want to spend hundreds on custom cables. Also the future build only has a Rosewill Photon 550w which doesn't really have many compatible cables. I've read that you shouldn't mix up cables and to use cables meant for your psu. Does this apply to cable extensions too, or are extensions universal? I want to get something like these.

 

[lvt]

I want a nice look for an upcoming build but I don't want to spend hundreds on custom cables. Also the future build only has a Rosewill Photon 550w which doesn't really have many compatible cables. I've read that you shouldn't mix up cables and to use cables meant for your psu. Does this apply to cable extensions too, or are extensions universal? I want to get something like these.

Cable extensions are safe, I automatically include 24-pin cable extensions for my computers for better cables management. And it will facilitate motherboard removal.

But those I use don't cost that much, they usually cost $5~$10 each.