Random connection problems ...

Many USB 2.0 devices are not recognized .... when adding a USB 2.0 extension to this extension USB3 USB 2.0 device is generally recognized. More rarely USB 3.0 devices' hard disk) are also not recognized as they are when the branches are directly ....
I do not know if my copy is defective or if the problem is general.
As the extension works with some devices I missed the deadline and could not return the product. So mistrust
It is better to put a few euros more for a reliable product.

Edit of 10/29/14
I quite radically alters my review: indeed after ordering and recently tried a brand extension USB3 and "high end" (and therefore "high price ..." lifetime guarantee I see that recognition problems are much the themselves and more or less random. Now I think the problem is related to Windows 8.1 (or OS drivers). I fixed the problem after numerous fruitless searches and testing (uninstall reinstall all USB drivers, the chipset motherboard etc.) by disabling the "Quick Start" in the depths of the Control Panel -> Power Options -> choose the action power buttons -> disable the fast start.
It remains true that all this is for the user ragent a recent PC, no pirated software, branded computer still under warranty etc ..
That he is not competent in computer will be unable to deal with these problems.
I leave the initial comment in thinking he could possibly be used for other.