What are these?

[Delusional]

I've been seeing these "Deck Shells" show up alot recently on magic sites. I'd just like to know (since the product description is quite vague) What are these? http://www.penguinmagic.com/p/S5754

 

[veteran]

They're a utility that allow the magi to inconspicuously switch a deck. I cannot tell you more for fear of exposure.