It's the classic die-box with CDs!
The magician displays a real Compact Disc to the audience and places it into the left side of a plastic case. The CD then "disappears" according to the magician, but the audience could clearly see the CD simply slid to the other side of the case...or so they thought. When the magician opens up both doors on the case, the CD is nowhere to be found! The magician may then reproduce the CD from anywhere (his pocket, perhaps...).
Comes complete with Case, CD and instructions.