It's actually much cheaper... http://www.weldingcity.com/?subcats=...search&x=6&y=4
When you click on any of those parts you'll see a chart with what part numbers fit what or follow this link> http://www.weldingcity.com/tig-consu...llet-body.html
It's all very simple, the gas lens just replaces the regular collet body and you'll use the standard collets with them. Alumina cups for gas lenses screw on to the gas lens and use the same insulator that came with your torch.
If you have any questions just ask. Edit: Here's a nice poster from CK Worldwide to illustrate http://www.ckworldwide.com/CK_POSTER.pdf If you need a pdf reader to open it, I like free file viewer http://www.freefileviewer.com/ it's very small and safe... decline on all the add ons when you install it, works great.