Traycard / Inlay Card – This is the paper part that is embedded in the back of the case under the disc that is not removable. It usually has the barcode and track listing on it, and also has the side spine text (artist name) that you see when cases are stacked.
The CD tray is a slim double case and hinged near the spine. The way it is molded can hold a CD on each side. Chubby CD Jewel Case: This case, also called the fatty case, is a way to hold multiple discs in one case.