Hi Abra! Thanks so much for stopping by the metal butterfly wings card :D
It's a special kind of duct tape. It looks like duct tape but it's a bit shinier with a peel off backing. It's used to seal ductwork for air conditioning or heating systems. It works a lot better (and I think any metal tape would) if we adhere it to cardstock first. Then it holds the shapes better when die cut or embossed.
Hi, Abra - Just saw your funny comment about CAS! We were ALL new, just like you. And for me, it was just a couple years ago :*
CAS = "Clean And Simple" or like totally uncluttered, streamlined, yet still pretty.
This is not to be confused with CASE = "Copy and Share Everything" that's what we do when we see a beautiful card we want to try and copy, to learn how it was done. We say "This is a CASE of so and so's card which you can see here (put a link of his or her original card) and here is my version of it..." You can see a list of cardmaking acronyms by googling it, or by going directly to: