... Muffler is installed on the air power equipment (such as fan, air compressor, boiler vent, generators, water pumps and ... "and12".Welcome to your inquiry. Product informationRemarksProduct name Efficient Duct mufflersize 4" miniDuct mufflerFine structure ,Practical, Strong,Appearance ... a good working environment2.ues for air power equipment (fan, air compressor, boiler vent, generators, water pumps and ...