The term case refers to the boxes in which waves of Transformers toys are shipped to retailers.
Since Beast Wars, case assortments have consisted of toys of the same size class. During Generation One and Generation 2, when the concept of size classes had yet to be formalized, case assortments were typically made up of toys that shared a common gimmick.
Main article: Shortpacking
A solid case consists entirely of multiple units of a single toy. Solid cases are typically used to ship "big ticket" toys that effectively occupy size classes all to themselves, such as 20th Anniversary Optimus Prime or Ultimate Bumblebee.
A notable drawback of solid cases is that they can lead to supply outpacing demand to the point where the toy becomes a shelfwarmer. This typically happens when normally sized and priced toys (such as Beast Wars Inferno) are shipped in solid cases.