Keep case

Besides DVD-Video films, keep cases are very common with most disc-based video games since the PlayStation 2, and they are also found on many PC titles and MP3-CD audiobooks (all use discs that are the same basic dimensions as a DVD).

The first products to be released in keep cases were VHS tapes,[citation needed] though most were stored in less expensive pressboard sleeves.

In the days before video games were released on optical media, cartridges would rarely come packaged in specially designed plastic keep cases with lugs inside to hold the instruction manual, as opposed to pressboard boxes.

Cartridges and cards for the Master System platform were the first video games to be packaged in any kind of keep case.

The cases are made of soft, clear or colored, polypropylene plastic with a transparent polyethylene outer jacket, usually with a printed paper sleeve behind it.

[1] The structural differences between a CD and a DVD have led many manufacturers to study different hub designs for keeping the DVD (or the DVDs, in multi-disc cases) in place: unlike CDs, which are made from one layer of plastic material, DVDs have two layers, which are thinner (so that together they reach the same thickness of a CD) and not bonded all the way to the center.

The individual cases are color-coded, with blue being used for Blu-ray and red for HD DVD, and the format displayed prominently on a stripe above the cover art.