If you connect a lot of device , you need another power supply which is not includedThe High Quality 4 port Usb Hub Connects to scanners, printers, digital cameras, camcorders, speakers, mice, keyboard, external drives, MP3 players and moreAll slots can be used at the same time for data exchangeCompatible with many systemsExtends 4 USB 2.0 ports to your computer with up to 480 Mbps data transfer rateUSB cable length: about 55cm.100% new and High quality 4-port USB 2.0Hub Adapter with ON/OFF Switch.Perfect for your PC, laptop, Notebook and Macbook.Support plug and play, no extra driver needed.USB 2.0 interface, backwards compatible with USB 1.1.Data transfer rate up to 480Mbps.Can be used to connect USB devices such as a USB webcam, USB mouse, U-disk, USB keyboard, printers, scanners, etc.Each USB port with ON/OFF switch, for easy to control.Blue LED indicator.Individual port over-current protection.Compatible with Windows 98SE/2000/ME/XP/Vista, Linux, Mac OS.This Hi-Speed USB 2.0 4-Port Ultra-Mini Hub provides four downstream USB ports for Plug-and-Play connectivity to your USB 1.1 and USB 2.0 devices. A perfect lightweight travel tool, this compact hub tucks easily into the pocket of your laptop bag, and requires no extra power supply. It offers an ideal way to connect on the road, and virtually anywhere you need fast, handy access to your USB devices. An LED light power indicator makes sure you always know when you're connected and ready to go.