From the engine description:
Crafted from solid brass, stainless steel, and aluminum by a German engineering company, the engine has a precisely calibrated carburetor, spark plug, and piston that generate maximum mechanical energy in a smooth, efficient manner. Fueled by butane (available at camping stores), the engine starts by turning its flywheel. A piezo magneto is attached to a timing disk that sends an electrical impulse to the spark plug, igniting the fuel within the cylinder. An adjustable fuel valve controls the engine's speed and the simple yet elegant movement of the valve rod, cross head, and crankshaft are clearly visible at lower revolutions.
Here's where you can check out this gorgeous desktop combustion engine.