Missing on web site is the instructions inside the box: To ensure stable connections, connected devices should not exceed a combined current of 900 mA. Devices are usually rated as follows: Mouse IOO mA Camera 300mA Keyboard 500 mA External Hard Drive 900 mA I needed 2 external HD I'll get a more appropriate model. I have other Anker products which I like, so I'm sure there is something. Have to also check the computer USB 3 specs