The standard
packaging for a
DVD.
A clamshell package is made of plastic. It's hinged on the left side and closes with a clasp on the right. There is usually a sleeve of flexible plastic around the outside to hold a label, and there is often a pair of clips on the inside left to hold a track list. On the inside right is a stubby spindle gadget like what you'd find in a jewel box.
The most convenient thing about a clamshell is that it is the same height as a VHS tape, but about half its width. This allows DVDs and tapes to be shelved together.
So called because the shell of a clam is hinged.