VMMUF: Noise-reducing Exhaust Muffler The Model VMMUF Noise-reducing Exhaust Muffler attaches between the central vacuum’s exhaust port and the exhaust piping system. The muffler greatly reduces the sound level of the central vacuum’s exhaust system. The Model VMMUF noise-reducing muffler is compatible with all AirVac Central Vacuums. A muffler is included standard with AirVac Gold, AirVac AVR and AVP Series Central Vacuums. Features Reduces annoying central vacuum system exhaust noise Installs between vacuum and exhaust system piping