I bought the Hub for my Raspberry Pi and for one of the cheapest decided consciously, as most favorable not encapsulate the 5V supply voltage and provide only the actual available to consumers, but also to the PC (Raspberry) return. For a PC that can be deadly and damage both the motherboard and power supply - for me and my Raspberry the perfect complement because of this the power of the stroke can be used as operating voltage and therefore I do not need a separate power supply for the operation!