Use this little stainless beauty to teach teenagers and older students how heat engines work Then keep it on your desk, where you deserve to have it! This low-temperature-differential Stirling engine is beautifully machined. It works with hot water, ice water, a combination of hot water with ice cubes, or a hair dryer. The bigger the temperature differential the faster it runs. It measures 5-3/4" tall with a 3-5/8" dia flywheel and a 3-1/2" dia x 7/8" tall base. DSTAR engines has a complete line of external heat engines using similar parts so each item can be used in a educational setting and have them look as a complete set. If you need support for any DSTAR engine just contact DSTAR.