The Western Digital 1TB My Book Essential Edition 2.0 Hard Drive helps enable eco-friendly PCs, yielding average drive power savings of 4-5 watts over other drives. Energy-conscious users can build systems with higher capacities and the right balance of system performance, ensured reliability, and energy conservation. Plus, the Western Digital My Book Essential Edition 2.0 Hard Drive has an amazing 1TB of storage for archiving your most important data.