This gadget is a barebones adapter for mildly tech-savvy people to connect a 2.5″ or 3.5″ hard drive to your computer’s USB port.
I’ve been using it for about six months, and have attached a variety of drives (IDE and SATA) to my Mac, to a PC, to a VirtualBox Windows VM, and to a dedicated NAS box running Linux. I’ve consistently used it without installing dedicated drivers (and for that matter, without reading the installation guide which is provided on CD-ROM).
For the same money (about $20) you could get a USB enclosure that keeps your drive better protected, but then you’d be locked into one specific drive size and connector type. The Vantec adapter is flexible across several drive types (2.5″ v. 3.5″, SATA v. IDE) , and comes with adapters for both the data and power connections.
I reach for this gadget when I need temporary access to a drive–usually because I took the drive out of another machine and need to get data off before it dies. Or, because I need to format a drive before it gets installed elsewhere, or just for a fast data transfer.