Vetus MV100 Plastic Exhaust Muffler with Check Valve (102mm Diameter)Vetus MV100 marine exhaust muffler constructed from plastic, designed to reduce noise from the exhaust system. It is particularly suitable for boats where there is no room to install a waterlock and or a gooseneck. The MV series muffler includes a built in check valve on the exhaust inlet side. This check valve ensures that water that goes into the muffler can never flow back out of it towards the engine, eliminating the need for a gooseneck. The