According to the web page description this item... has a luminous gyroscope?... has removable & interchangeable parts... has a bulb that lights up... and comes with an extra flywheel & allen key. That's all great and sounds like a fun item, but in reality: the "gyroscope" does not light up - I suspect a dead battery, no extra flywheel was included & no allen key was included, so there is nothing to remove & interchange, the engine can barely generate 2.5V - so the 5V bulb is never going to lite up. Oddly after a few minutes of running this engine now does not even work. It does need to heat up before running but now even after 5 minutes of direct flame this engine just won't run. I can only post 1 video so I cannot show the "dead" engine. Overall I can't give this more than 1 star for the overhyped description & missing parts