Efficient and optional power supply included
I bought this product several months ago for an Asus laptop that didn't have an ethernet connection and wasn't getting good wifi in a room.
It's very handy because you can use this box directly for ethernet (gigabit), without needing to use the optional power supply. You can also connect low power USB devices.
I have not tested the data rates, but I have not noticed any particular problems.
And when I need to connect external USB3 hard drives, I use the power supply. In fact, in this case, you end up with quite a few cables on your desk...
You can't see it on the picture, but the optional power supply plugs into a female socket next to the 10cm "small extension cable" (male usb in the top right of the picture).
So I'm happy with this purchase.