This 20GB internal desktop drive by Western Digital, model WD200BB-75DEA0 from the Caviar product line, is a reliable storage solution for both PC and Mac users. With a rotation speed of 7200 RPM and a cache of 2MB, it ensures speedy access to stored data. The drive type supported is HDD and it comes in a 3.5-inch form factor. The WD Caviar hard drive is silver and black in color and features enhanced IDE (EIDE) and IDE interfaces. It can be used as n internal Hard Drive or can be used in an IDE / EIDE removable storage (external) HDD cases / devices. The item dimensions are 5.75 inches in length, 4 inches in width and 1 inch in height. The package includes one unit of the drive which is made in Malaysia. HDD S/N: WD-WMAD22831233.