MoKo Superspeed USB 3.0 4-Port Compact Hub Bus-Powered With 0.65 ft USB 3.0 Cable For Ultra Book, MacBook Air, Windows 8 Tablet PC, Black Portable square shaped size (2.4 x 2.4 inch), ultra-slim and convenient to carry. With this device, you can easily extend 4-USB ports for tablets, mobile devices, and other USB devices, eliminating the trouble of switching among devices. Super speed USB 3.0 port enables data transfer rate up to 5Gbps. Backward compatible with USB 2.0(High Speed 480Mbps),USB 1.1(Full Speed 12Mbps). Compatible with Window 7 / 8 / 8.1 / Vista / XP, Mac 9.1 above OS without installing drive. Safely protect devices and charger with short circuit, open circuit protection, plug and play. With no drivers required, this device gives you access to immediate, blistering speeds.