Saw this, thought it was a bit tacky so had to have it! Advertised as a Cupids Arrow Stirling Engine, it isn't technically a Stirling Engine. It's a type of hot air engine known as a Thermoacoustic heat engine. This type of engine doesn't need a flywheel, as the air trapped in the cylinder vibrates back and forwards making the piston move in and out rapidly.
Unfortunately it seems a bit fussy in operation as I've been unable to get this engine to run for any longer than several seconds at a time.
![](https://i.ytimg.com/vi/rSfq7i6uIoE/maxresdefault.jpg)