Low-temperature Stirling Engine Motor Model Diy Kit. FEATURES: A Stirling Engine is a Heat Engine That Operates by Cyclic Compression 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. The Teacher Can Make the Explaining Process Much Straightforward and Students Can Better Understand Its Principle. Run Freely on the Top of a Cup of Hot Water, No Need to Fire an Alcohol Lamp, Safer for Children. The Start Temperature Difference Between the Product Bottom Contact and Circumstance Shoulder Be Greater Than 25. Gently Flip the Wheel, then It Can Run Itself. An Exquisite Frosted Plunger Can Avoid Steam Leakage and Reduce Abrasion. If the Friction Between the Flywheel and Support is Big, Please Use a Little Graphite Dry Lube to Quiet It Down Nicely. Don't Use Oil, Because It Will Lead to Oil Dirt. SPECIFICATIONS: Material: Stainless Steel + Spray Paint Carbon Steel + Glass Principle of Operation: Heating Expansion / Cold Compression Speed: 180rpm (max.) Size: 12.2 * 10.2 * 10.2cm / 4.8 * 4 * 4" Weight: 250g / 8.8oz INCLUDES: 1 * Low-Temperature Stirling Engine Model DIY Kit 1 * User Manual(English) . We are an international seller, your order will be shipped from abroad so please allow the necessary time of minimum 14 working days for delivery right now depending on where you ship to, due to ongoing delays in postal deliveries globally.