Looks good and works very well.. Smaller than I thought it would be.. Clever engineering design with the magnet in the piston.
I really like this product, especially since it uses a magnet instead of a mechanical connection to control the black disk "displacer". I find that I need to be careful not to use too hot a heat source to make it work; I used a cup of water that was between warm and hot when I stick my finger in to test the temperature. If it is too hot, the glass piston tends not to go down. Too cold, the glass piston gets sucked to the bottom. I can also get the engine to spin a little faster for a short time by temporarily touching an ice cube to the top plate.
Bought it as a gift for my teenage daughter aspiring to become an engineer. It didn't require assembly so it has less issue. It works great and spins fast. The noise depends on how the mechanism is in place. You can move it here and there to lessen the noise. It even continued to spin for a period of time even after it was removed from the mug (heat).
We put this on the table whenever we have our grand kids for dinner.
I have few low temp sterling engines and this one is by far the best. Your morning coffee could power this thing for a over an hour; so fast and so quietly too. Love it.