With this USB3 3.5" hard drive holder, you can take an internal hard drive from a desktop computer and plug it into your Mac. hard drive holder does not need any software and supports full USB3 speeds of up to 5gbps. 

Hard drive holder comes with all cables and adapters, allowing a power supply, USB3 cable, aluminum box and bracket for the hard drive. 

USB 3.0 3.5" Hard Drive holder can use all 3.5" hard drives that use SATA 100/150/300 Sata2, i.e. all killer hard drives.

For example, the hard drive holder can be used if your external hard drive is broken and you need a new board to attach it to the hard drive. There are a lot of external hard drives that break too early because their chips break.

This is probably the cheapest external hard drive you can get because an internal hard drive is always cheaper than an external one and this box is cheap.

The hard drive holder is made of plastic and aluminum so it lasts as well as possible, it is made so you don't need a spectacle puller either to open it or put a hard drive in it, however it is secured as well so even if you transport the hard drive there is no chance of hard drives sticking apart. 

Hard drives can take all normal 3.5" hard drives, i.e. those that are not made thicker to get more space on them. The holder can take hard drives up to 8 tb.