STA-BIL Carb/Choke and Parts Cleaner is formulated to dissolve gum, varnish, dirt, and carbon deposits. Once clean, your engine will start faster and easier and idle more smoothly. This product also helps restore lost mileage and performance. Cleaner includes a convenient spray nozzle which comes with a extension tube that lets you reach harder to access areas. Leaves behind no oily residue. Safe for oxygen sensors and catalytic converters.