djuiinostar low temperature stirling engine djuiinostar this engine is driven by the temperature differential between the top and bottom plates. to make temperature differential, simply put it on a cup of hot water or on top of ice. the speed depends on the temperature differential: the higher, the faster. it can reach a speed of 180-200 rpm when in good condition. what's it for:<br> *funny gift<br> *kids' science project<br> *hobby<br> *physical/mechanical learning<br> *put on your table<br> *you want to spend money but don't want to spend too much<br> features:<br> * stand: carbon steel; top and bottom plates: nickel-plated carbon steel; power cylinder and piston: glass; displacer: pvc foam; displacer cylinder wall: plastics; displacer guide: copper; flywheel, cranks, rods, shafts or so: stainless steel. brand: djuiinostar<br> model: dltd-303<br> speed: 60-200 rpm(revolutions per minute)<br> start temperature differential: about 20 celsius/68 fahrenheit<br> material: carbon steel, nickel-plated carbon steel, stainless steel, glass, bronze, pvc foam and plastics*<br> overall size: 103x103x125mm/4.06x4.06x4.92in(l/w/h)<br> size of flywheel: 87x5.8mm/3.43x0.23in(diameter/thickness)<br> inner diameter of power cylinder: 15.6mm/0.61in<br> net weight: 238g/0.52lb<br>