Color:USB 3.0 7 Port w/ Charger Description Tendak USB 3.0 Hub is designed for expanding USB connections of laptops/computers. Features 7 USB 3.0 ports and one smart charging port. Specifications 7 USB 3.0 ports for data transfer 1 Charging port for charging phone/tablet etc. LED: 7 built-in blue LEDs Switcher: 7 ON/OFF power button Cable length: 100 cm / 39 inches Symtem Supports: Windows 10.1/ 10/ 8.1/ 8/ 7/ Vista/ XP/ 2000 and Mac OS X 10.2 or above / Linux 9 or above USB Port Supports: backwards compatibility with USB 2.0/1.x version USB 3.0 data transfer rates: Up to 5 Gbps (ten times faster than USB 2.0) Why need a 5V 3A power adapter USB3.0 port on laptop/desktop provides only 900mAh of current, it's really not enough if you have multi usb devices. Some devices require more power such as external hard drive, one external hard drive requires 0.5A to 1A of current, you can't plug other devices in if only 900mAh with the power adapter, you can charge the phones/tablets (iphone requires 1A, Samsung require 2.1A) It can charge your phone even if the computer is off. If without the power adapter, the USB hub will be shutdown when the computer is off What is included 1 x USB 3.0 Hub Warranty: 1 Year Limited Warranty by Tendak Note Some USB 3.0 devices and 2.4G wireless devices(wireless mice, wireless keyboard etc.) require a direct connection to host USB 3.0/2.0 ports may not compatible with this product. It comes 5V 3A power adapter. Don NOT make the total of current over 3A when charging your multiple devices.