Crazy run with double flywheel ----- Double flywheel Stirling runs much faster than single flywheel Stirling. The engine will run wild and generate due to the heat from the premium alcohol and the twin flywheels. This is a very and imaginative toy. -Made ---- Plates are made of Russian pine wood and are manufactured with fine grinding; the cylinders and pistons of the engine are made of fine aluminum alloy; the connecting rods of the displacer pistons are made of finely ground bearing steel. The engine also uses quartz glass tubes as hot cylinders to reduce the risk of bursting while burning. Easy to operate and long lasting - fill the alcohol with 95% alcohol (we recommend this ) and light it. Let the light burn on the cylinder at the rounded end for about 20 seconds, then push the lightly and it will work like a charm. It can run continuously for more than 8 hours without any damage, tested by one customer. Sturdy Packaging - Glass tubes are packed separately from bubble bags to avoid damage during shipping. Easy to remove the packaging and put it back . The wooden is exposed and unpainted. You can your and it your own or with your kids and . Priority gift option for many apps ---- this is an amazing and fantastic product for this . elegant gift wrapping makes it look pretty and pretty. It has a wide range of applications, as a great gift for children's science projects, physics/mechanical learning, teacher classroom presentation props, , family, parents, children's birthday gifts, etc. Many of our clients are from schools, colleagues, etc. size:183x90x90mm Material:Aluminum alloy colour:As Shown Package Contents: 1 set x Stirling principle engine Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.