Although "flat wrap" is a common industry term, we prefer "deflated wrap."
Or the German: "Deflaturwrap."

It's Raining Dells (Sheet) Price: $ 4.25 Item Code: FWLI0004 This is Todd’s daughter, Delphine. She gets 12 cents for every sheet we sell. Quantity: 1 flat sheet Size: 20" X 30" Printing: Litho on uncoated, 100% post-consumer waste paper Packaging: Shipped flat QTY: