Duct Fan Silencer, 4-Inch [+$39.99] None Ducting Ducting 4", 25-Feet Long [+$19.99] Ducting 4", 8-Feet Long [+$13.99] None Clamps Duct Clamps 4", Stainless Steel , 2-Pack [+$6.99] None Noise Reduction Clamps Noise Reduction Clamp, 4-Inch [+$12.99] ...