The main material from which the body of the pocket is made.
— Plastic / rubber. This category includes models that use plastic and/or rubber in the construction of cases. The specific ratio and features of the use of these materials are different: the body can be all-plastic, have rubber lining at the ends to increase impact protection, be completely covered with rubber, etc. And in covers (see "Type"), these materials can also be supplemented with others — such as EVA, neoprene or even cloth. Anyway,
plastic / rubber cases are found exclusively in external models, including docking stations. Such pockets are somewhat inferior to metal pockets in terms of strength and reliability, but they are cheaper, and in normal everyday use, the mentioned difference is not critical.
— Steel. Cases made of
metal are most often made of steel, but there are other options (for example, aluminium alloys). In the inner pockets, only this option is found — this is due to a number of features of such accessories. As for external models in this design, they are much stronger and more reliable than plastic ones, besides, the metal case creates an additional feeling of solidity. The downside of these advantages is the higher price.
The number of separate slots for drives provided in the design of the pocket, in other words, the number of drives for which this model is designed.
In addition to models for
one slot, nowadays you can find more capacious solutions — for
two drives, or even
more. Such "multiplying" is found in three types of devices. The first is large-format pockets for stationary purposes (see above), operating in the format of separate storages for a large amount of data. Such models may support RAID arrays (see above) and other special features. The second type of devices with more than one slot are separate docking stations (see "Type") with similar functionality. The third type is server models (see "Purpose") with an internal installation; they again allow the organization of arrays, but by means of the server itself.
Note that external devices with one slot can be powered from the USB port, but several drives in this case inevitably require a separate PSU (see "Power").
