G-Technology 1TB G-DRIVE mobile with Thunderbolt and USB 3.0 Portable External Hard Drive, Silver - 0G03040 Ultra-fast Thunderbolt and USB 3.0 data transfer 7200RPM hard drives  up to 136 MB/s (As used for transfer rate, megabyte per second (MB/s) = one million bytes per second. Performance will vary depending on your hardware and software components and configurations) Bus-powered hub eliminates the need for a separate power connection Solid aluminum case, ultra-stylish profile makes for easy portability Up to 1TB storage capacity handles documents, music, digital video and photo files (As used for storage capacity, one gigabyte (GB) = one billion bytes and one terabyte (TB) = one trillion bytes. Total accessible capacity varies depending on operating environment). Time Machine Compatible, works on Mac and PCs