THIS ENGINE WAS DESIGNED AND BUILT BY AN OVERSEAS CRAFTSMAN IN HIS HOME MACHINE SHOP! He has been involved in model engineering and building engines for about 10 years. All his engines are tested on compressed air to make sure they are running as they should, then tested on steam to check for tightness or leaks. This engine is NOT a made in China engine. I have been involved with model steam engines for quite some time, and this engine is by far the best quality, best looking, best smooth running engine I have come across in a long time. This engine weighs in at just under 3lbs. Flywheel is around 1 1/2" in diameter, has a piston bore of 12.7mm and a stroke of 16mm. The crankshaft is supported by 5 double ball raced bearings. I ran this engine, it is self starting and runs on a minimal amount of air. It does not have a reversing gear. THIS ENGINE IS A QUALITY BUILD!