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.
Clasp
— Magnet. Clasp based on the action of a strong permanent magnet. When it is closed, the magnet “sticks” to a special metal element on the other half of the cover, or, in the case of flips (see “Type”), to the body of the tablet. The main advantages of such a fastener are simplicity of design and durability: the magnet practically does not wear out, does not lose efficiency over time, and does not suffer from frequent opening/closing. As a disadvantage, one can name a relatively weak fixation; however, magnetic fasteners are usually designed to minimize this disadvantage and are reliable enough for most applications. Thanks to this, the magnet is one of the most popular types of fasteners. At the same time, we note that when using covers with such clasps, you need to exercise some caution: they should not be placed next to credit or other magnetic cards, because a magnet may render such a card unusable.
— Hook-and-loop. The Hook-and-loop fastener consists of two surfaces: on one there is a layer of felt, on the other — microscopic hooks that catch on the felt fibers when the surfaces come into contact. This provides a fairly strong grip. The disadvantage of Hook-and-loop is increased wear with frequent use, because. with each opening, part of the fibers breaks out with hooks. Therefore, such fasteners are rather poorly distributed; they are mainly used in bags (see "Type"), where opening and closing the clasp is relatively infrequent.
— Elastic. Elasti...c fastening that holds the two halves of the case together. Due to its design features, it is used exclusively in covers (see "Type"), but among this type of covers it is only slightly less common than a magnet (see above). The fact is that the rubber band combines simplicity and reliability of holding, while it does not pose a danger to magnetic cards. Among the shortcomings, one can name a tendency to stretch with inaccurate use (due to which efficiency is lost), and in general, somewhat less durability than a magnet.
— Rivet. Another popular name is "button". By design, such a clasp is similar to a regular button used in clothes: on one half of it there is a curly protrusion, on the other — a recess with a special lock. When closed, the protrusion fits into the recess and locks into place, ensuring a secure fit. Actually, the reliability of retention is the main advantage of rivets. On the other hand, they may require considerable force to open and close. This, firstly, is not very convenient, and secondly, it wears out the material around the button a lot — up to loosening and falling out of the fastener with a relatively intact case. This puts forward separate requirements for the strength of the case itself. Because of all this, rivet fasteners are quite rare.
— Lightning. The zipper is used exclusively in bags (see "Type"), and more often than any other type of fastener. This is the best option given the main purpose of bags: zippers close and open easily and quickly, are quite durable and even provide some degree of additional protection at the ends.
— No zipper. Fasteners, by definition, do not have protective covers (see "Type"); also, models without fasteners are often found in bags that leave one end of the device open and are designed for the fastest access to a tablet or e-book. In other types, this option is quite rare. Also in this category are bags with a drawstring that tightens the inlet neck.
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.
Material
The material from which the cover is made determines its protective properties and a number of other features. To date, cases for tablets and e-books can be used:
— Textile. This type of materials is quite diverse: it includes both soft thin fabrics, designed more to protect against accidental scratches, and dense materials, comparable in strength to plastic and capable of protecting against fairly strong impacts. Almost all fabrics are pleasant to the touch and look good, especially since almost any colour can be given to this material. However, their cost is quite low. Thanks to all this, the fabric is one of the most common materials for covers today; it is used in covers and bags. Different fabrics have different composition, which should be taken into account when cleaning and/or washing such a cover. Among the shortcomings can be called instability to moisture — most fabrics get wet one way or another. At the same time, water-repellent impregnation can be applied to eliminate this.
— Silicone. Polymeric material based on silicon or organosilicon. The advantages of silicone are elasticity, impermeability and resistance to temperature extremes and ultraviolet radiation, due to which it is well suited for dust and moisture-proof covers (see "Dust and water protection"). Disadvantages — Tendency to stretch and lose elasticity over time. It is used quite rarely, and almost never occurs in e-books.
— Rubber. This material combines low cost,...softness, scratch resistance and good protection of the device inside both from scratches and from shocks and shocks, as well as moisture (rubber is waterproof). In addition, the cost of rubber is quite low. The disadvantages are increased sensitivity to temperature changes and wear. Because of this and a number of other reasons, rubber booties are quite rare.
— Plastic. One of the most popular materials used in tablet cases; in e-books is used much less frequently. The advantages of plastic are low cost, good rigidity, resistance to moisture and temperature changes (both the material itself and the protection it provides to the tablet), as well as a bright appearance — plastic can be given almost any colour. The main drawback is that it tends to crack on impact, but in fact it should be quite a strong blow, which is likely to damage the inside of the tablet as well.
— Skin. A kind of fashion material, designed for those who care not only about the functionality, but also about the stylish appearance of the case — leather goods look very solid. The skin is durable, almost waterproof and resistant to temperature changes. The main disadvantage is the difficulty in maintenance: products made from this material require periodic processing with special means and special conditions for cleaning and drying, otherwise cracks and deformations may occur. In addition, leather is quite expensive.
— Leatherette. An artificial analogue of genuine leather: it is much cheaper, while it may not differ much in appearance. Another advantage of leather substitutes is ease of care — they do not require such care as genuine leather. However, they are also characterized by a number of disadvantages inherent in inexpensive materials: a tendency to scuff, sensitivity to temperature changes, as well as a slightly lower strength than genuine leather. In modern cases, various types of leather substitutes are used, differing in price and characteristics; usually, the quality of such material directly depends on the cost.
— Wool. A soft material that resembles a dense thick fabric in its properties (see above). Wool protects the device well from temperature extremes, and also provides some degree of impact protection due to its thickness and softness. However, due to a number of features, in particular the complexity of processing, this material is very rare in cases for tablets and e-books.
Auto on/off
With this function, the case actually turns into a control device for a tablet or e-book: when the screen is closed, the gadget is automatically put into sleep mode, when opened, it goes into working mode. This eliminates the need for the user to turn the device off/on manually every time, and also provides significant energy savings. This function is found only in specialized cases (see "Compatibility"), and the specialization must be extremely accurate — even similar models from the same manufacturer may not work correctly in such a case.
