Waveline Outboard Motor Flusher Muff Round Cup Type. Engine attachment for flushing outboards with clean, fresh water attaches to the hose with supplied with connector. A must to clean and rinse the cooling ports of salt, helps provide clear flow of cooling water around the outboard engine powerhead and lower down through the impellor. Muff size  95mm Diameter Hose size 12mm Please note these flush muffs are generally not suitable for outboard engines 6HP or less as the gearbox is not wide enough to form a good enough seal to stop excess fresh water escaping.