Never buy from StrongU.
I bought the STU-U6 from them. They advertised 660 GH/s @ 1300Watts. After long delays, they say that they will deliver the STU-U6 but with reduced capacity and increased electric consumption of 440 GH/s @ 2200 Watts.
At this capacity, the equipment is not profitable at my power cost of 0.12 $/kWh. StrongU refuses to refund the money and insists on delivering the "Waterdown" equipment. Stay away from this company. They will get your money and send you Junk!