USB 3.0 Power Adapter 4/7 Port Multi USB Splitter Hub USB Hub 2.0 USB Multiple Expander Switch 30CM Cable Hub Docking Stations Notice -1- Not used for charging, it is used to provide more usb ports to transfer files. -2- The power supply specification is 3.5*1.35mm 5V 1A, and supports hard drives below 1TB. If your hard drive is larger than 1TB, then the power supply is not suitable for you. -3- This link has 9 options, if you want USB 3.0 with power supply, please select the correct option you need. -4- The power supply can solve the problem of insufficient power supply. If you need to work with a hard disk, then you should choose a power supply. Please note that please do not use more than two hard disks at the same time. -5- The power supply can increase the USB transmiion speed, and the insufficient power supply will cause the data transmiion to be reduced, garbled codes, and the power supply can improve the reliability. Specification -1- Item Name: USB HUB 3.0 / 2.0 -2- USB Ports: 4/7 -3- Color: Black/White Features -1- INDEPENDENT SWITCH Expand your computer's connectivity with this 4/7-port USB hub with inp> -2- BATTERY LIFE Inp> -3- MULTIPLE USB PORTS Instantly add 7/4 (USB 2.0/USB3.0) ports to any electronic device by plugging it into your computer, and then connect your mouse, keyboard, external hard drives, flash drives, and so much more! -4- EASY TO SET UP & CONVENIENCE Takes up very little space, so its handy as a good partner for travel, office, home and school.