I am pretty knowledgeable about these kind of things. I own a Jackery 1000, which I love. This offer looks really good on the surface. 2200 Watt hours for $1000 is about half the cost per Wh of a Jackery or a Yeti (goal zero). Interpreting their hype, they are apparently using 21700 type cells (the same as a model 3), rather than 18650 size (which is what a Tesla model S uses. 21700 is mildly better, but it is not a big difference. Just more Watt-hours per cell, and a physically larger and heavier cell (21 mm diameter, 70 mm long). As others have mentioned, there is a lot of hype here. For example, saying that their pack is just four batteries makes no sense. (Probably it includes a string of 4 groups, with each contains about 35 cells. I'll do the math if anyone asks.) The bottom line is: this price is not impossible if they are selling at cost. But I am a little too worried by their hype to actually buy one now. At this price this would be very competitive with a power wall (Tesla) with portability and no installation hassle. I would buy one in a minute if I believe that they were for real. There is not reason why someone can't built this and the weight is plausible is you had great engineering pushing the limits. (The weight of the cell alone to make 2200 watts is about 22 lbs.) A reasonable price for this would be $2000 or so. SO, it could be a bargain, but I am not planning to risk it.