Even after some research, it is not clear what this thing is. But at about half price, I had to look into it.
Amazon listing - slightly different product but this one has reviews:
https://www.amazon.com/dp/B00JM5M3Z4/ref=psdc_3613854011_t1_B00JB9N1C0
Company website
The comments on Amazon indicate that it comes with no instructions and people who bought it can’t figure out what to do with it or the included items (some wires). The company’s website doesn’t list the product though it has similar ones. There is a pervasive poor quality of English there that gives one pause. The Amazon listing claims it can heat water up to boiling; I find this unlikely, but if it manages to boil the vessel it is floating in, that would be fun to watch.
It appears that this is supposed to float in something like a pool. If that’s the case, it should consist of the panel, made watertight, something to make it float, and a heating element. It seems to lack the latter, judging from the amazon reviews.
So this thing appears to be a $220 solar panel ($1/watt is a decent price for one) on a $20 rubber mat, hopefully made waterproof. Normally sold for $1600, available here for half the price, but not actually functional as a water heater without adding an element. (If you just stick the wires in the water, even at low voltage it could be dangerous. I’m not sure it will heat the water, but it might electrolyze it, also fun to watch.)
This is ignoring the alternate plan, that you could probably sit the black mat at the bottom of the body of water this is supposed to float in and it would heat the water with higher efficiency than this panel will. Thermal collectors are much more cost effective in general for heating water (ie, sit object in the sun, it will get warm).
Now maybe if this panel was remote mounted, a wire could run into a heating element in a tank; that’s a situation where it might be useful. For example, on top of an RV heating a small tank inside. But that doesn’t appear to be what this thing is at all.
So I’m not saying this thing is a scam to cash in on people who will buy anything with solar in the name, but I’m not not saying it is, either.
Would love to hear from someone who understands it better.