2 and 4-stroke compatible thanks to removable 4-stroke bung sleeve Tapered design fits most exhaust diameters Silicone rubber core construction is sturdy and durable Supplied with lanyard for easy removal and storage Prevents water or contaminates entering the exhaust during cleaning Directions for use: 1. Ensure the exhaust is fully cooled, 2. For 2-stroke exhaust remove the black silicone sleeve from the bung, for 4-stroke exhaust keep the black silicone sleeve on the bung, 3. Insert and twist the exhaust bung into the end of the exhaust to form a perfect, 4. Carry out your cleaning and maintenance routine and 5. Always remove before starting the engine. MUC-OFF EXHAUST BUNG