... noise device. Product information RemarksProduct nameEfficient duct Muffler size 6 inch mini and 6inch Duct mufflerFine structure ,Practical, Strong ... 2.ues for air power equipment (fan, air compressor, boiler vent, generators, water pumps and other vent noise larger ... 4.Simple structure, practical 5.Sound-absorbing effect:25DBA 6.Easy Install 7.No maintenance required. Packaging1.Whellote-box ...