G-LEAF 4" Muffler Inline Fan Noise Reducer Duct Silencer G-LEAF 4-Inch Duct Silencer Two Accurate 4 Inches Flanged Ends for installing Qucikly. Decreases Inline Fan Noise Up To 50% By G-LEAF Dust Silencer With Wave Sound Rreducing Foam. Durable Light Aluminum Body,Portable Size Is Easy To Assemble. Use With Duct Fan And Carbon Filter Combo,Grow Tent,Light Systems more.