More USB ports when you need them. Comes with 4 USB 3.0 ports that deliver extremely fast speeds. Enjoy data transfer rates up to 5 Gb/s. Compatible with USB 2.0 and 1.1. Built in USB 3.0 cable. Features: Adds 4 USB 3.0 ports to you computer Supports both USB 3.0 and USB 2.0 Super fast speed USB bus-powered (no AC adapter required) Compact design and built-in-cable for maximum portability Hot swappable and plug-n-play Must Buy Reasons: Specially designed for MacBook Air iMac and new MacBook Pro (Retina) Works with Windows PC Quickly adds 4 USB3.0 ports into your computer Supports all USB devices including USB drive printer webcam keyboard and mouse etc Backward compatible with USB2.0 computers and devices Just works without AC adaptor needed 2-tone stylish and anodized aluminum housing System Requirements: Mac OS X 10.7 to 10.10 and above Windows XP/Vista/7/8 and above Any desktop and notebook computer with available USB 3.0 or 2.0 port.