I gently used it in the past but wiped it off and it has 1TB storage. It’s ready to use on either Mac or Windows! Model:0G03040 With a 1TB capacity, this G-Technology G-DRIVE mobile with Thunderbolt 0G03040 external USB 3.0 hard drive offers plenty of space for your digital media. The portable aluminum case provides durability, making it easy to safely take your files on the go. * 1TB storage capacity- Provides ample space for music, movies, games and other digital data. * USB 3.0 and Thunderbolt interfaces- For flexible connectivity options. Bus-powered to eliminate the need for power cables and cords. * Data transfer rates up to 136MB/sec.- Enable a rapid response when updating files. * 7200 rpm speed- Delivers fast performance. * Portable aluminum case- Offers durability to help ensure safe transport. * Compatible with Mac and PC (reformatting required)- For use with your existing computer. Also compatible with Apple Time Machine.