The thermo-acoustic heat engine is something which I don't really understand. I seems to work, though. The maker is unknown but it appears to be made in China.
The engine consists of a glass tube, half filled with wire wool, with a single light weight piston at the other end, connected via a thin wire to a crank on a flywheel. The tube is heated at about it's mid point by a small meths burner. I've very little idea how it works and I can only refer to the Wikipedia page at Thermoacoustic heat engine, which is too generic to help much.
It was purchased new and appears to be in good condition. It doesn't work as well as I think it could but that may be normal for these devices. Draping a wet cloth over the cold end of the tube does seem to help.