Opaque cases made of soft plastic made by Amaray that DVDs often come in. They have a polyethene outer jacket into which a sleeve can be inserted. Inside, they have a set of clips to hold the linear notes. There actually seem to be several different coppies of keep cases, differentiated by the type of clasp that holds the disc in, but I guess only the original is the real thing. Probably the best type of DVD case. They're about the same size as a VHS box, but only ~15 millimetres thick.

See also: Jewel case, snap case