It is a rechargeable power not electric power
I enjoyed the product that's the very reason I came back to re-order it after 2 years. However, it got changed from electric power to rechargeable power, also the color changed from black to silver. To me, it seems the electric powered unit has more power than the rechargeable one. A big disadvantage of rechargeable power unit is that you may not use it while it is in charge, which is over 12 hours. Plus, you don't know when it has been completely recharged. For me, I charged it for about 20 hours initially, and the indicator still stays orange, which I assume it should turn to green after 16 hours. Of course the rechargeable unit will give you portable ability without an adapter, while I seem don't care it too much.
Rating: 4 stars