Screen size
The screen size of the device the case is designed for. This parameter directly determines the dimensions of a compatible tablet or e-reader. A device with a larger diagonal will simply not fit into the case, however, smaller sizes than those indicated in the case specifications are also not recommended — at best, the device will hang inside (which will negate many advantages), and at worst, it will not stay in the case at all .
It should be noted that this parameter is critical if you select a universal cover (see "Compatibility"). If the specifications directly indicate compatibility with the model of your tablet or reader, the screen size is for reference only, because. case by definition is optimized for the dimensions of the respective device.
Compatibility
Compatibility of the cover with a specific tablet or e-book model — or the lack of such specialization, in the case of universal models.
For many popular models of tablets and readers, their own specialized covers are produced. They are much better suited for such devices than universal ones, since they are initially “sharpened” for the specific features of a particular model: the dimensions and shape of the case to the nearest millimetre, the location of controls, connectors, cameras, etc. This is especially true in the case of tablets. And for protective covers (see "Type") this is generally the only possible option.
At the same time, universal covers have a wider scope: in fact, in this case, compatibility is determined only by the screen size (see above). This can be useful, for example, if your family has two devices of the same size, but only one of them is taken on trips: you can buy one bag and use it for the desired gadget.