All three models are USB 3.0-equipped and come bundled with the company’s SmartWare software, which performs automatic and continuous backup tasks. They are also backwards-compatible with USB 2.0, of course, and support both Windows and Mac OS X operating systems. The drives will be available at retailers and Western Digital's own online store starting at $100 for the 500GB My Passport Essential, $139 and $170 for the 750GB and 1TB My Passport Essential SE, and $250 for the 3TB My Book – though it’s available in 1 and 2TB versions as well. Internally, the latter uses a WD Caviar Green drive which will be available shortly as a standalone product according to the company.