The WD Elements USB 3.0 portable hard drive offers reliable, high-capacity on-the-go storage, fast transfer speeds, versatile connectivity and large capacity for cost-conscious consumers. This 1TB hard drive is compatible with the latest USB 3.0 devices and backwards compatible with USB 2.0 devices. It is also available in 2TB, 3TB, 4TB, and 5TB models. When connected to a USB 3.0 port, the WD Elements portable hard drive delivers fast data transfer speeds. When the internal hard drive is almost full, your computer runs slower. Don't delete files.