Case Mod - UV Wires

I’ve done a few simple mods to my PC case (added cathod lights and LED string) and I want to make it look a lot more tidy inside. I’ve seen a few pictures on Case modders websites that look like the wires between components are wrapped inside some UV over-cable.

This is the only picture I can find whilst I’m at work:

Bigger picture below

I have a basic idea of how it works and I’d love to do it because it looks slick… and it would help tidy up the insides of my computer so it doesn’t look like someone stuck a shotgun to R2D2’s head inbetween my hard drives…

The only problem is… I have no idea what they are called or what the process of putting them inside these over-wires is. If anyone can throw in a phrase or two to help me find them (UK by the way, incase different names etc for it) I’d be grateful.