Visible Window Single-cylinder, Four- stroke Nitro powered, Air cooled engine, including stand. This a unique Toyan engine in that it has a clear window on the cylinder head. You can see into the engine as it’s running and see the entire combustion process. Spark, ignition combustion and piston movement are all clearly visible! Great for education and curious young minds who wish to see how an engine works! Newly designed silencer system makes the engine run quieter. Window shows internal combustion! Great for RC, Desktop, and more! Perfect for the RC or miniature engine enthusiast!