Features: How it Works A Stirling engine is a heat engine that operates by cyclic compressio n and expansion of air or other gas (the working fluid) at different temperatures, such that there is a net conversion of heat energy to mechanical work. A Great Explanation Teacher can make the explaining process much straightforward and students can better understand its principle. Safe Opeartion Run freely on the top of a cup of hot water, no need to fire a alcohol lamp,safer for children. Operating Requirement Start temperature difference between the product bottom contact and circumstance should be greater than 25& 8451;.   Easy to Use Gently flip the wheel, then it can run itself. Considerate Design Exquisite frosted plunger can avoid steam leakage and the reduce abrasion. Note: If the friction between flywheel and support is big, please use a little graphite dry lube quiet it down nicely. Don't use oil, because it will lead to oil-dirt. Specifications: Model: LL-001 Wheel Color: Gold / Purple (Optional) Material: Stainless Steel +  Spray Paint Carbon Steel + Glass   Principle of Operation: Heating Expansion / Cold Compressio n Speed: 180rpm (max.) Item Size: 12.2 * 10.2 * 10.2cm / 4.8 * 4 * 4" Item Weight: 250g / 8.8oz Package Size: 17.3 * 9.5 * 11cm / 6.8 * 3.7 * 4.3" Package Weight: 333g / 11.7oz Package List: 1 * Low Temperature Stirling Engine Model DIY Kit 1 * User Manual(English)