So Mobile OTB is an external portable hard drive with USB 2.0 connection. It is equiped with a OTB button (One Touch Backup) which will quickly copy all your data with a single press on it. You can bring it everywhere in your pocket. Technical Specifications: Rotation Speed: 5400rpm Average Seek Time: 12ms Interface: 1x High Speed USB 2.0 (USB 1.1 Compatible) Power Supply: Self powered via USB port and/or AC/USB Cable Drive Weight: 190g Dimentions: 3.11 x 4.92 x 0.63 inches (7.9 x 12.5 x 1.6cm) 2 Years Limited Warranty System Requirements USB 2.0 Windows ME, 2000, XP or Vista.