The Western Digital My Passport for Mac 2nd-gen is an ultra-portable, external hard drive built specifically for the Macintosh OS X operating system. It in fact requires zero installation, as its plug-n-play compatibility allows it to automatically configure itself to the Mac computer. It is available in two sizes (320GB/500GB) and connects via a USB 2.0 interface. This allows the drive to deliver data at approximately 480 Mb/s. Signature to the My Passport for Mac is its quiet operation, which unfortunately does tend to render the unit somewhat hot. But extensive tests by critics has proven that the drive can withstand extended tear, abuse, and heat without any unwanted interruptions in data processing.